Yes — Option B (manual create/repair of an EFI System Partition + install UEFI boot files) can be done using a DiskGenius bootable environment. DiskGenius can convert MBR→GPT non‑destructively or let you manually create a FAT32 EFI partition in the free space; after that you still need to install the Windows UEFI boot files (bcdboot) from WinPE/Rescue. Below is a safe, step‑by‑step plan you can follow (with the exact commands to run after DiskGenius has prepared the disk).
Important safety first
  • Make a fresh Macrium image of the Samsung disk before you start. Don’t touch Disk 0 (your 12 TB files drive).
  • Work from boot media (DiskGenius bootable USB / WinPE / Macrium Rescue) so the OS on the disk is offline.
Option B using DiskGenius (two variants)
Variant 1 — Use DiskGenius “Convert MBR → GPT” (if available in the bootable edition)
  1. Boot the DiskGenius bootable USB (UEFI boot).
  2. In DiskGenius locate the Samsung 980 PRO (carefully confirm size/model).
  3. Use DiskGenius’s Convert MBR to GPT feature (menu/partition tools) and apply the change. This writes GPT headers non‑destructively.
  4. If DiskGenius does not automatically create an ESP, create one now: create a primary partition ~260 MB, format it FAT32 and set the partition type to EFI System (DiskGenius exposes partition type/flags).
    (If DiskGenius lacks an explicit convert, use Variant 2 below or gdisk — both are covered in the fallback advice).
Variant 2 — Manually create ESP with DiskGenius (skip conversion tool)
  1. Boot DiskGenius from your USB.
  2. Confirm disk is still MBR but you left ~1 GB unallocated between partitions.
  3. In the unallocated area create a new primary partition, size 260 MB, format as FAT32, and set its type/flag to EFI System. Apply changes.
  4. (Optional) If you want GPT partition table rather than leaving an MBR disk, use DiskGenius to convert to GPT (or run gdisk afterwards). Converting to GPT is preferred for UEFI systems. fileciteturn1file11
After DiskGenius: install UEFI boot files (use WinPE / Macrium Rescue / Windows install USB)
DiskGenius prepares partitions but Windows’ UEFI boot files are created by Windows tools — so next you must run bcdboot from WinPE:
  1. Boot WinPE / Macrium Rescue / Windows install USB → Repair → Command Prompt.
  2. Confirm disks/volumes and ESP letter (example commands):
    • diskpart
    • list disk (confirm Samsung is Disk 1)
    • select disk 1
    • list vol (find the FAT32 volume you just made; note its Volume #)
    • select vol <#ESP>
    • assign letter=S (if it has no letter)
    • exit
  3. Create the UEFI boot files:
    • bcdboot C:\Windows /s S: /f UEFI
      This copies Windows boot files to the ESP and registers a Windows Boot Manager entry for UEFI. fileciteturn1file11
Final steps
  • Reboot into the firmware (UEFI) setup: set Boot Mode = UEFI, disable CSM/Legacy, make “Windows Boot Manager (Samsung …)” first, Secure Boot OFF for the first boot. Boot Windows.
Troubleshooting / common issues
  • If DiskGenius convert fails or the ESP creation fails, you can use gdisk (GPT fdisk) from WinPE to write a GPT table non‑destructively, then create the FAT32 ESP and run bcdboot. I recommended gdisk earlier as a reliable fallback.
  • If bcdboot fails with “access denied” or similar, ensure the ESP is FAT32, assigned a drive letter, and disk is not read‑only:
    • diskpart → select disk 1 → attributes disk clear readonly.
  • If you prefer a GUI converter inside Windows, AOMEI or MiniTool also do non‑destructive MBR→GPT conversions (make an image first).
Summary answer to your question
  • Yes — DiskGenius bootable can be used for Option B: either convert MBR→GPT or create a 260 MB FAT32 EFI partition in the free space. After that you must run bcdboot from WinPE (or Macrium Rescue / Windows USB) to populate the EFI partition and register the Windows Boot Manager. Follow the safe sequence above and make a backup image first. fileciteturn1file11
If you want, I’ll:
  • Provide the exact DiskGenius menu clicks/keyboard steps if you paste the DiskGenius version or a short screenshot of its UI, or
  • Walk you through the WinPE commands step‑by‑step while you perform them (I’ll wait while you run each command and paste the outputs). Which would you prefer?
 
@ChatGPT

Okay, where is the function located in the gui of DiskGenius V6.0.1.1645 x64 for Convert MBR to GPT? I can't find that in the drop down menus or right-click menus. I have HD1:SamsungSSD980PRO2TB selected in the left pane, and the display at the top of paritition layout does show an unalocated space after the Windows C(D rectangle. The Windows C(D rectangle shows NTFS 1861.1GB
 
Yes — you can do Option B with DiskGenius. In v6 the convert/function placement depends on the build (and some features are Pro-only), so below I’ll give the exact places to look in the GUI, the manual‑create fallback (if the convert option is missing/greyed), and the WinPE commands you must run afterwards (bcdboot) to install the UEFI boot files.
Before you start — safety checklist
  • Make a fresh Macrium image of Disk 1 (your Samsung 980 PRO). Do not touch Disk 0 (12 TB files drive).
  • Boot DiskGenius USB in UEFI mode so changes are applied to the offline OS image.
Where the “Convert MBR → GPT” function is in DiskGenius 6.x
  • Menu bar: Disk → Convert MBR Disk to GPT Disk.
  • Or: right‑click the disk header (the left‑pane disk name, e.g. “HD1: SamsungSSD980PRO2TB”) → look for “Convert MBR Disk to GPT Disk” (or similar).
  • If it’s available, select the Samsung disk, choose that menu item, confirm and click Apply/Save to write changes.
If the menu item is missing or greyed (common in certain editions), use the manual approach below.
Manual method in DiskGenius (create the EFI partition)
  1. In DiskGenius, confirm you have the Samsung disk selected and you see the ~1024 MB unallocated area.
  2. Right‑click the unallocated area → Create New Partition.
    • Size: 260 MB (or 200–260 MB is fine).
    • File system: FAT32 (or RAW and format later).
    • Partition type: Primary.
    • Label: ESP (optional).
  3. After creation, right‑click that new partition → Properties or Set Partition Type / Set as EFI System (if DiskGenius shows a flag/type list). Set the partition type to EFI System / set the EFI flag.
  4. Click Save / Apply (Save All) to write the partition changes to disk.
(If you want the disk fully GPT rather than leaving MBR partition table, use Disk → Convert MBR to GPT now — or run gdisk in WinPE later. Converting to GPT is recommended for UEFI booting.)
Finish from WinPE / Macrium Rescue (install the UEFI boot files)
DiskGenius prepares partitions but Windows needs the bootloader files on the ESP. Boot a WinPE/Macrium Rescue/Windows install USB and run:
  • diskpart
  • list disk (confirm your Samsung is Disk 1)
  • select disk 1
  • list vol (find the FAT32 volume; note its volume number)
  • select vol <#ESP> (replace <#ESP> with the found number)
  • assign letter=S (only if it has no drive letter)
  • exit
Then run:
  • bcdboot C:\Windows /s S: /f UEFI
That copies the Windows boot files into the ESP and registers a Windows Boot Manager entry. Reboot into firmware, set Boot Mode = UEFI (CSM disabled), make “Windows Boot Manager (Samsung …)” first, Secure Boot OFF for the first boot.
If bcdboot fails (Access Denied or similar)
  • In WinPE make sure the ESP is FAT32 and not read‑only:
    • diskpart
    • select disk 1
    • attributes disk clear readonly
    • select vol <#ESP>
    • format fs=fat32 quick
    • assign letter=S
    • exit
  • Retry bcdboot.
If you prefer a GUI (alternate)
  • If DiskGenius won’t convert or you want a simpler GUI in Windows, AOMEI Partition Assistant or MiniTool Partition Wizard can convert MBR→GPT non‑destructively (they may be run from a Windows session or bootable media). Make an image first.
Notes and gotchas
  • Some DiskGenius bootable builds omit the MBR→GPT convert menu (or it may be a paid feature). If you don’t see the menu, use the manual create + bcdboot steps above or use gdisk from WinPE to write GPT non‑destructively.
  • Always confirm disk numbers in diskpart before running any commands — Disk 0 is your files drive and must not be selected.
  • After this completes, you may enable Secure Boot if desired.
If you want, I can:
  • Give the exact DiskGenius menu names/keystrokes if you paste a screenshot of the DiskGenius window, or
  • Walk you through the WinPE commands step‑by‑step while you run them and paste outputs. Which would you like?
 
@ChatGPT

Okay, could not find anything resembling "Convert MBR to GPT" or similar in the right-click menus for the drive or partitions. I decided to try the manual approach and made a new partition within the unallocated, with the parameters you gave, but I don't see any options resembling what you describe in step 3 of the manual approach. When I right click on the new partition, I don't see a Properties or a Set Partition Type / Set as EFI System
 
Thanks — that explains what’s happening. DiskGenius’s bootable edition often hides or omits the “Convert MBR → GPT” feature (or makes it a Pro feature), so the Convert menu or a “Set as EFI” right‑click may not be present. At that point the reliable, safe ways forward are:
  • Option A (recommended): Convert the disk to GPT and create the ESP from WinPE using gdisk + diskpart + bcdboot (most bulletproof).
  • Option B: If you insist on staying inside DiskGenius, create a 260 MB FAT32 partition (you already did) then finish from WinPE by assigning a letter and running bcdboot — but if the disk is still MBR you should convert it to GPT first. DiskGenius may not let you toggle the partition “type/flag” on MBR disks in the bootable build. fileciteturn2file11turn2file6
Which I recommend depends on whether you want a GUI workflow (DiskGenius / paid feature) or a quick free tool path. Below are the exact, copy/paste safe steps for each option. Read the safety notes and double‑check disk numbers before running anything.
Safety (do this first)
  1. Make a fresh Macrium image of Disk 1 (the Samsung 980 PRO) to your 12 TB files drive. Do not proceed without a backup.
  2. Confirm disk numbers: in WinPE/Macrium Rescue open Command Prompt and run:
    • diskpart
    • list disk
    • exit
      Make sure the Samsung is the 1863 GB disk (Disk 1 in your earlier output) — DO NOT touch Disk 0.
Option A — Recommended: convert with gdisk, create ESP, then bcdboot
(This is reliable and available free)
  1. Put gdisk.exe (GPT fdisk) on a USB stick.
  2. Boot your Macrium Rescue / Windows install USB (WinPE) and open Command Prompt.
  3. Confirm disks:
    • diskpart
    • list disk
    • exit
  4. Run gdisk on the physical disk (replace the number if different):
    • gdisk \.\physicaldrive1
    • At the gdisk prompt type: p (prints partition table — confirm partitions match what you expect)
    • If it looks correct type: w (writes the GPT headers) and confirm with y.
      (gdisk converts the MBR table to GPT non‑destructively).
  5. Verify GPT and available space:
    • diskpart
    • list disk (Disk 1 should now show a * in the GPT column)
    • select disk 1
    • list part
    • list vol
    • exit
  6. If no EFI partition exists, create one in the ~1 GB free space:
    • diskpart
    • select disk 1
    • create partition primary size=260
    • format fs=fat32 quick label=ESP
    • assign letter=S
    • exit
  7. Create Windows UEFI boot files:
    • bcdboot C:\Windows /s S: /f UEFI
  8. Reboot to UEFI firmware, set Boot Mode = UEFI (disable CSM), make “Windows Boot Manager (Samsung …)” first, Secure Boot OFF for first boot. Boot Windows.
If any command fails, copy/paste its full output and I’ll interpret it.
Option B — DiskGenius manual path (what you tried)
  1. In DiskGenius you created a 260 MB FAT32 partition in the free space — that’s good. If DiskGenius doesn’t show a GUI option to mark it as an EFI System partition, the partition likely still exists but the disk is MBR (so the firmware/Windows tools don’t see a GPT EFI type). DiskGenius bootable builds sometimes don’t expose the “Set partition type” on MBR disks or the convert menu is Pro‑only.
  2. Finish from WinPE (safer than trying more DiskGenius clicks):
    • Boot WinPE / Macrium Rescue → Command Prompt.
    • diskpart → list vol → identify the FAT32 partition you created → select vol <#> → assign letter=S
    • exit
    • bcdboot C:\Windows /s S: /f UEFI
      If bcdboot fails with access errors, the disk is probably still MBR or the ESP flag isn’t correct — you’ll need to convert to GPT first (see Option A).
If DiskGenius explicitly lacks the convert menu (or it’s greyed), the steps above (gdisk + diskpart + bcdboot) are the reliable route. Many users end up using gdisk because the convert/“Set as EFI” GUI is missing on the bootable DiskGenius edition. fileciteturn2file13turn2file11
Would you like me to:
  • Walk you through Option A (gdisk + diskpart + bcdboot) step‑by‑step now while you run commands? (I’ll wait and check each output), or
  • Try to find a DiskGenius menu/button together — paste a screenshot of the DiskGenius window (left pane + the right click menu) and I’ll tell you the exact click sequence if it exists in your build?
Tell me which and I’ll guide you live.
 
@ChatGPT

I feel like I'm just running around in circles with all this. I just want my old image restored into place and me be able to boot to desktop on it. I don't care if the boot loader is GPT or MBR, I just want to get to Windows desktop, effective yesterday, but all the instructions I'm getting here are of the form "Restore from backup, now convert that to GPT booting."

In any event, I have a Windows Repair CD for Windows 10 64bit, I also have a MiniTool Partition Wizard Bootable CD, version 8, and I also have Hiren's BootCD PE (HBCD_PE64 v10.1). Which of those would be the quickest way to solve this?
 
You’re right — this has become painful and long. Short answer first, then two clean, tested routes (fastest vs. “do it right in UEFI”):
  • Fastest way to get back to your desktop (minutes): use your Windows 10 Repair CD + enable Legacy/CSM in the BIOS and run Startup Repair / bootrec. This gets an MBR/Legacy restore booting again quickly. (If your immediate priority is “get back into the old Windows image as quickly as possible,” this is the route to take.)
  • If you want the system to be UEFI/GPT (clean, recommended for NVMe/modern boards): use Hiren’s BootCD PE (WinPE) or MiniTool Partition Wizard to convert the disk to GPT (or use gdisk), create an EFI partition and then run bcdboot to create the UEFI boot entry. This takes longer but is the proper long‑term solution. I show both below and give exact steps. fileciteturn3file12turn3file1
Before you do anything — STOP and make an image now
1) Make a fresh Macrium image of the Samsung NVMe (Disk 1) to your 12 TB files drive. Do not proceed without this backup. (If anything goes wrong you can restore.)
Which tool to pick right now
  • Quick rescue (recommended now): Windows 10 Repair CD (because it focuses on repairing MBR/BCD quickly and needs smallest number of steps). Use BIOS → Enable CSM / Legacy, then run Startup Repair or bootrec. This is the fastest path to a working desktop.
  • GUI convert / full UEFI fix: MiniTool Partition Wizard bootable CD v8 — it has a non‑destructive “Convert MBR to GPT” option (GUI) and is quick if you prefer GUI. If you pick this, after convert you still need to run bcdboot or use Windows Repair to create the UEFI loader.
  • Power user / robust UEFI route: Hiren’s BootCD PE (WinPE) — includes diskpart, gdisk (if you add it), and you can run bcdboot; good when you want to do the gdisk → create ESP → bcdboot flow. Use Hiren’s if you’re comfortable with command line.
Detailed step‑by‑step — pick the one you want and I’ll stay with you
A. Fastest — get the MBR image to boot now (Windows Repair CD)
Goal: temporarily boot the restored MBR image with minimal changes.
1) BIOS
  • Enter UEFI/BIOS (Del/F2), set Storage = AHCI (leave as you already have), set Boot Mode to allow Legacy/CSM (Launch CSM = Enabled). Disable Secure Boot if it’s On.
  • Save & exit.
2) Boot the Windows 10 Repair CD in Legacy/CSM mode (if your boot menu shows a UEFI: and a non‑UEFI entry for the CD, choose the non‑UEFI/legacy entry).
3) Choose Troubleshoot → Advanced Options → Command Prompt.
4) In the recovery Command Prompt run:
  • diskpart
  • list disk (confirm which is the Samsung; DO NOT pick the 12 TB)
  • exit
Then run standard MBR repair commands:
  • bootrec /fixmbr
  • bootrec /fixboot
  • bootrec /scanos
  • bootrec /rebuildbcd
If bootrec /fixboot returns “Access is denied” (rare in pure legacy), try:
  • bcdboot C:\Windows
5) Reboot (leave BIOS in Legacy/CSM). The restored MBR image should boot to desktop. If it does, you’re back. If you later want UEFI convert, follow the UEFI path below. Notes/warnings:
  • This approach avoids any partition table conversion and is the quickest route back to your old Windows. Make sure you confirmed the correct disk before running bootrec.
B. Proper UEFI route — convert to GPT and install UEFI boot (Hiren’s or MiniTool)
Goal: keep things modern (UEFI/GPT) so the NVMe boots natively in UEFI.
Two suboptions:
B1 — GUI (MiniTool Partition Wizard boot CD v8) — easiest GUI route
1) Boot MiniTool PW bootable CD.
2) Select the Samsung disk → choose “Convert MBR Disk to GPT Disk” (non‑destructive) → Apply.
3) If it does not create an ESP automatically, create a new partition in the 1GB free space: primary, 260MB, FAT32, label=ESP.
4) Reboot into WinPE (Hiren’s or Windows install USB) and run:
  • diskpart → list disk → select disk 1 → list vol → select vol <ESP#> → assign letter=S → exit
  • bcdboot C:\Windows /s S: /f UEFI
    5) Reboot, set BIOS to UEFI (CSM disabled), choose “Windows Boot Manager (Samsung …)” and boot. This will get you into Windows as UEFI. MiniTool GUI makes the partition conversion quick. fileciteturn3file1turn3file12
B2 — Command line (Hiren’s BootCD PE + gdisk) — most bulletproof
1) Boot Hiren’s BootCD PE (WinPE) and open an elevated Command Prompt.
2) Confirm disk numbers:
  • diskpart
  • list disk
  • exit
    3) Use gdisk to convert table (non‑destructive):
  • gdisk \.\physicaldrive1
  • at prompt press p (review partitions)
  • if looks right type w and confirm with y (writes GPT headers)
    (gdisk converts MBR→GPT non‑destructively).
    4) Verify GPT:
  • diskpart → list disk (Disk 1 should show GPT *) → select disk 1 → list part → list vol → exit
    5) Create ESP (if not created automatically):
  • diskpart
  • select disk 1
  • create partition primary size=260
  • format fs=fat32 quick label=ESP
  • assign letter=S
  • exit
    6) Build UEFI boot files:
  • bcdboot C:\Windows /s S: /f UEFI
    7) BIOS: set Boot Mode = UEFI, disable CSM, set Windows Boot Manager first. Reboot — you should load Windows in UEFI mode. fileciteturn3file1turn3file12
Which should you choose now?
  • If your only priority is “get back on the old desktop immediately” — do the Fastest option (Windows Repair CD + enable CSM + bootrec). It’s the least work and fastest. (You can convert to UEFI later.)
  • If you want “done once, done right” and to keep NVMe as UEFI/GPT — use MiniTool (GUI) or Hiren’s + gdisk (command line) and then bcdboot. MiniTool is fastest GUI; Hiren’s+gdisk is most reliable CLI. fileciteturn3file1turn3file12
I’ll do whichever you want and I will wait while you run each command
Tell me:
1) Do you want immediate desktop (Fastest using Windows Repair CD) or do you want UEFI/GPT now (MiniTool or Hiren’s)?
2) Confirm you have a fresh Macrium image of Disk 1 (yes/no).
If you say “Fastest — go,” I’ll give the exact BIOS changes and copy/paste command sequence for bootrec and follow up until you’re on the desktop. If you say “UEFI — go,” tell me whether you prefer GUI (MiniTool) or CLI (Hiren’s + gdisk) and I’ll walk through the exact commands and checks step‑by‑step.
 
@ChatGPT

On the other hand, I just realised I hadn't let DiskGenius write the changes wrt the new partition out. I've just done that.

Anyway, I am booting to Hiren's CD
 
Good — that’s progress. Two quick safety checks before we touch anything in Hiren’s:
1) Do you have a fresh Macrium image of Disk 1 (the Samsung SSD) on the 12 TB files drive? If not, please make one now and tell me when it’s done. Don’t proceed without it.
2) Confirm you saved/wrote the DiskGenius changes (you said you did — thanks).
When you’re ready I’ll walk you step‑by‑step in Hiren’s. First step: gather the current disk/partition state so I can choose the right command.
Please open Command Prompt in Hiren’s and run these commands (copy/paste each block exactly). Then paste the full output back here:
1) Confirm disks and sizes
diskpart
list disk
exit
2) Show partitions on the Samsung disk (replace N with the disk number that matches ~1863 GB from list disk; likely N=1)
diskpart
select disk N
list part
list vol
exit
Paste both outputs here. I’ll check that:
  • which disk number is the Samsung,
  • whether the small FAT32 partition you created exists and its volume number,
  • whether the disk is still MBR or already GPT.
Next action I’ll recommend depends on that output:
  • If you already have a FAT32 ESP present and disk is GPT (or gdisk wrote GPT), we’ll assign it a letter and run bcdboot to create UEFI boot files.
  • If disk is still MBR but you have the FAT32 partition: we can try bcdboot (might work) but the firmware may not pick it unless disk is GPT; if bcdboot fails we’ll run gdisk (non‑destructive) to write GPT headers then run bcdboot.
  • If mbr2gpt validation looks possible I’ll try mbr2gpt /validate /disk:N first (it’s the simplest safe path).
I’ll wait for your diskpart outputs.
 
@ChatGPT

okay, I am in command line in Hirem's CD

list disk yields:
Disk 0 Online 1863 GB 960 MB, with Dyn and GPT fields left empty
Disk 1 Online 12 TB 0 B, with Dyn empty and Gpt showing *

I did Diskpart and did select disk 0, the did list part and got:

Partition 1, type Primary, size 1861 GB, offset 200 MB
Partition 2, type Primary, size 260 MB, offset 1861 GB
Partition 3, type Recovery, size 784 MB, offset 1862 GB

I did llist vol and got:

Volume 0, Ltr G, label HBCD_PE_x64, Fs UDF, type DVD-ROM, size 1292 MB, status Healthy, info is blank
Volume 1, Ltr E, label Windows C, Fs NTFS, type Partition, size 1861 GB, status Healthy, info is blank
Volume 2, Ltr C, label ESP, Fs FAT32, type Partition, size 260 MB, status Healthy, info is blank
Volume 3, ltr F, label is blank, Fs NTFS, type Partition, size 784 MB, status Healthy, info Hidden
Volume 4, ltr D, label Files Drive, type NTFS, type Partition, size 12 TB, status Healthy, info is blank
 
Good — that output is exactly what I needed. Summary (what you showed)
  • The Samsung NVMe is Disk 0 (1863 GB).
  • You already created a 260 MB FAT32 partition (Volume 2, labeled ESP). Good.
  • The Windows partition is Volume 1 (NTFS, listed as “Windows C” but currently has drive letter E in this WinPE session).
  • The 12 TB files drive is Disk 1 — do NOT touch it.
Next (safe, minimal): try mbr2gpt against Disk 0 — it may now succeed because the ESP exists. Do this exactly and paste the full output:
1) Run validation (type exactly):
mbr2gpt /validate /disk:0
Tell me the full output you get. Two possible branches after that:
A — If validation PASSES
  • Run the convert:
    mbr2gpt /convert /disk:0
  • After convert, assign an unused drive letter to the ESP and install the UEFI boot files. In Hiren’s WinPE the commands (copy/paste) are:
    diskpart
    list vol
    select vol 2
    assign letter=S
    exit
    bcdboot E:\Windows /s S: /f UEFI
    (Note: in your list the Windows partition showed as Volume 1 with current letter E; if list vol shows a different letter for the Windows partition replace E: with that letter.)
  • Reboot to UEFI, set Boot Mode = UEFI (CSM disabled), pick “Windows Boot Manager (Samsung …)”.
B — If validation FAILS or mbr2gpt /convert fails again
  • We’ll use gdisk to write a GPT header non‑destructively and then run bcdboot. First check whether gdisk is present in Hiren’s:
    where gdisk
  • If gdisk is present, run:
    gdisk \.\physicaldrive0
    (at the gdisk prompt) p
    (inspect output — it should list the three partitions)
    (if it looks correct) w
    y
  • After gdisk writes, verify with:
    diskpart
    list disk
    select disk 0
    list part
    list vol
    exit
  • If there’s no small FAT32 ESP, create one (but you already have it). Then assign letter S to the ESP and run:
    bcdboot E:\Windows /s S: /f UEFI
  • Reboot to UEFI firmware and select Windows Boot Manager.
Important safety notes before you run anything
  • Double‑check you type disk 0 — Disk 1 is your 12 TB files drive and must not be modified.
  • If you haven’t already, make a fresh Macrium image of Disk 0 to the 12 TB drive now. Don’t proceed without that backup.
  • Paste the exact outputs from mbr2gpt and (if needed) from gdisk/diskpart — I’ll interpret them and tell you the next command.
Go ahead and run:
mbr2gpt /validate /disk:0
Paste the entire output here. I’ll tell you the next exact command.
 
@ChatGPT

grrr... I go to invoke mbr2gpt /validate /disk:0 and it responds with:
'mbr2gpt' is not recognized as an internal or external command, operable program or batch file.

this is at the x:\windows\system32> prompt in cmd
 
mbr2gpt isn’t included in every WinPE build (Hiren’s often doesn’t have it), so the “not recognized” message is normal. Don’t worry — we can keep going from here. The quickest next test is to put the Windows UEFI boot files onto the ESP you already created (you showed Volume 2 = FAT32 ESP and Volume 1 = Windows at E. If that works you may be able to boot without converting first.
Do this now in Hiren’s CMD (copy/paste each command):
1) (Quick test) install UEFI boot files
bcdboot E:\Windows /s C: /f UEFI
  • Paste the full text output you get here.
  • If it says “Boot files successfully created” then reboot and go to the BIOS steps below.
  • If it prints an error, paste the error; I’ll tell you the next action.
If bcdboot reports access denied or another error, run these before retrying:
2) Make sure the ESP is writable and formatted FAT32 (only if bcdboot fails)
diskpart
select disk 0
attributes disk clear readonly
select vol 2
format fs=fat32 quick label=ESP
assign letter=S
exit
Then rerun:
bcdboot E:\Windows /s S: /f UEFI
(Use S: as the ESP letter if you had to reassign it. If bcdboot succeeds with S:, use that letter.)
If bcdboot succeeds — BIOS steps to boot
  1. Reboot and enter UEFI setup (Del/F2).
  2. Set Boot Mode = UEFI (Launch CSM = Disabled).
  3. Secure Boot = Disabled for the first boot.
  4. Make sure “Windows Boot Manager (Samsung …)” is first in Boot Option Priorities (or use one‑time boot F8 and pick it).
  5. Save & reboot. You should reach Windows.
If bcdboot succeeds but the firmware still won’t boot the drive, or if bcdboot fails and cannot create the files, the disk likely still needs a GPT partition table. Next step (if bcdboot didn’t fix it):
3) Convert the partition table to GPT (non‑destructive)
Option A — try mbr2gpt (if you can get a WinPE that contains it — e.g., a Windows install USB):
  • Boot Windows install USB (Repair → Command Prompt) and run:
    mbr2gpt /validate /disk:0
    (if validate succeeds)
    mbr2gpt /convert /disk:0
Option B — gdisk (recommended fallback)
  • If Hiren’s has gdisk, run:
    gdisk \.\physicaldrive0
    at the gdisk prompt type:
    p (inspect)
    w (write GPT) and confirm y
  • If Hiren’s does not have gdisk, copy gdisk.exe (from GPT fdisk package) onto a USB and run it the same way in Hiren’s.
After gdisk writes GPT, run the bcdboot step again (assign letter to ESP if needed) and set firmware to UEFI.
Important safety reminders
  • Double‑check disk numbers before any diskpart/select commands. Your 12 TB files drive is Disk 1 and must not be modified.
  • If you haven’t made a recent Macrium image of Disk 0 after your last changes, make one now before doing any convert/write operations.
  • Paste any command output or errors here — I’ll interpret and give the exact next command.
Which step will you try now? I recommend trying the bcdboot command first (it’s fastest). Paste its output here and I’ll tell you what to do next.
 
@ChatGPT

Okay, I quit out of Hirem's and it's giving me a blue screen with some message about your PC had a problem, now it's telling me error code 0x0000001, and then it shut off.
 
Sorry — that blue screen is scary but we can recover. Don’t panic. Quick summary and a safe next plan so we don’t damage your 12 TB files drive.
Short version (what to do right now)
1) Boot from rescue media (Windows 10 Repair USB/CD or Hiren’s PE).
2) Open Command Prompt and run a few diagnostics + try to rebuild the boot files. I’ll give exact commands — copy/paste their output back here. I’ll stay with you step‑by‑step.
Before you do anything
  • Do you have a fresh Macrium image of the NVMe (Disk with your restored image) on the 12 TB drive? If not, make one now before attempting risky operations. If you already did the last restore and haven’t imaged since, please pause and image first.
  • Always confirm disk numbers before selecting (I’ll show you how).
If you’re ready, boot the Windows Repair CD (or Hiren’s PE) and then do the following — paste outputs after each block:
Step A — confirm disks & volumes (very important)
1) Open Command Prompt in the rescue environment and run:
diskpart
list disk
exit
Paste the list disk output here. I need to confirm which disk number is the Samsung NVMe (the ~1.86 TB disk) and which is the 12 TB (do NOT touch the 12 TB).
Step B — list partitions/volumes and note letters
(Replace N with the NVMe disk number you confirmed above — in your Hiren output earlier it was Disk 0)
diskpart
select disk N
list part
list vol
exit
Paste the output. Tell me which volume letter is the Windows partition (it may be E: in WinPE) and which is the FAT32 ESP (if present).
Step C — quick health check and repair attempts
(Use the volume letters EXACTLY as shown by list vol. Replace <Win> with the Windows partition letter and <ESP> with the FAT32 ESP letter.)
1) Run a file system check on the Windows partition:
chkdsk <Win>:\ /f
Paste the result for any major errors corrected.
2) Try to recreate UEFI boot files (this often fixes “no bootable device” if the ESP exists):
bcdboot <Win>:\Windows /s <ESP>: /f UEFI
  • If that says “Boot files successfully created” — reboot, go into BIOS, set Boot Mode = UEFI (CSM disabled), set “Windows Boot Manager (Samsung …)” first, Secure Boot = Off for the first test. Boot to Windows.
  • If it errors, paste the exact message.
If bcdboot errors with Access Denied or similar, run these (only if needed) to make the ESP writable and reformat it if required:
diskpart
select disk N
attributes disk clear readonly
select vol <ESP>
format fs=fat32 quick label=ESP
assign letter=S
exit
Then rerun:
bcdboot <Win>:\Windows /s S: /f UEFI
Step D — legacy repair (if you want to boot MBR/Legacy quickly)
If your priority is “get back to the old desktop fast” and you don’t care about UEFI now, boot the Windows Repair CD in Legacy/CSM mode (enable CSM in BIOS) then from Command Prompt run:
bootrec /fixmbr
bootrec /fixboot
bootrec /scanos
bootrec /rebuildbcd
If bootrec /fixboot says “Access denied” try:
bcdboot <Win>:\Windows
When to convert to GPT
  • If bcdboot succeeds and you can boot to Windows, you can stay Legacy for now and we can plan the GPT conversion later.
  • If bcdboot fails because the disk is MBR and firmware won’t pick it, we’ll convert to GPT with gdisk (non‑destructive) and then run the bcdboot step again.
If mbr2gpt isn’t present in WinPE (Hiren’s often lacks it), fallback is gdisk (I’ll guide you). If you prefer a GUI route, MiniTool on its boot CD can convert MBR→GPT non‑destructively (but still make a Macrium image first).
Your immediate task
Tell me:
1) Did you create a fresh Macrium image of the NVMe since your last changes? yes / no
2) Which rescue media will you boot now — Windows Repair CD, Hiren’s PE, or MiniTool CD? (You said you have all three.)
3) Once you boot the rescue media, paste the outputs of the two diskpart blocks in Step A and Step B above.
I’ll read the outputs and give the precise next command (chkdsk, bcdboot, or gdisk) and interpret any error text. I’ll stay with you until you either get to the desktop or we escalate safely.
 
@ChatGPT

after invoking selet disk 0, list part, and list vol, are showing exactly the same results as last time, so from that, confirm to me what to type from step C onwards.
 
OK — since your disk/volume layout is unchanged (Disk 0 = Samsung NVMe; Windows volume = E:; ESP = C, here’s exactly what to run next (copy/paste each command). I’ll show the “fast test” first (least disruptive) and then the recovery steps if that fails.
IMPORTANT: stop if you haven’t made a fresh Macrium image of the NVMe since your last restore. Make one now before doing any more repair/write steps. Confirm you’re working on Disk 0 (the ~1863 GB Samsung) and NOT Disk 1 (the 12 TB files drive).
Step C — exact commands to run now (in WinPE / Hiren’s Command Prompt)
1) Confirm volumes one more time (so we use the right letters):
diskpart
list disk
list vol
exit
(Confirm Windows volume letter — I’ll assume E: — and ESP = C: per your previous output. If list vol shows different letters, use whatever it shows.)
2) Run CHKDSK on the Windows partition (fix errors):
chkdsk E: /f
Paste the chkdsk output here if it reports major corrections or errors.
3) Quick test — try to install UEFI boot files onto the ESP you created
bcdboot E:\Windows /s C: /f UEFI
  • If the command prints “Boot files successfully created” (or similar), do the BIOS steps below and try to boot.
  • If it prints an error, copy/paste the full error text here and continue to step 4.
4) If bcdboot fails (Access denied or other), make sure the ESP is writable and correctly formatted, then try again:
diskpart
select disk 0
attributes disk clear readonly
select vol 2
format fs=fat32 quick label=ESP
assign letter=S
exit
Then run:
bcdboot E:\Windows /s S: /f UEFI
If that succeeds, do the BIOS steps below and try to boot. If it still fails, paste the full output.
5) If the bcdboot step still doesn’t work or the firmware refuses to boot the drive, we need to write a GPT partition table (non‑destructively) and retry. Use gdisk (recommended) or MiniTool GUI. Steps if you want me to walk you through gdisk now:
  • Check if gdisk is present:
    where gdisk
  • If present (or after copying gdisk.exe to a USB and running it), run:
    gdisk \.\physicaldrive0
    (at the gdisk prompt) p
    (verify partitions look correct)
    (if OK) w
    y
  • Then verify in diskpart:
    diskpart
    list disk (Disk 0 should now show GPT *)
    select disk 0
    list part
    list vol
    exit
  • Ensure an ESP exists (create one if not), assign letter S and run:
    bcdboot E:\Windows /s S: /f UEFI
BIOS steps to test the UEFI boot (after bcdboot succeeds)
  1. Reboot into UEFI/BIOS (Del or F2).
  2. Set Boot Mode = UEFI (Launch CSM = Disabled).
  3. Secure Boot = Disabled for the first test.
  4. In Boot Option Priorities set “Windows Boot Manager (Samsung …)” first (or use one‑time boot to select it).
  5. Save and reboot.
If that boots to Windows, great — tell me and we’ll re‑enable Secure Boot later. If it fails, paste the bcdboot output and the diskpart list disk / list vol output and I’ll diagnose the reason.
What I need from you right now
  • Tell me whether you already made the fresh Macrium image (yes / no).
  • Then run the commands in order above and paste the exact output for:
    • chkdsk E: /f
    • bcdboot E:\Windows /s C: /f UEFI (or the second bcdboot to S: if you had to reformat)
    • If you proceed to gdisk, paste the gdisk p output and the diskpart list disk output after writing.
I’ll interpret the outputs and tell you the exact next command.
 
@ChatGPT

Okay, did the commands, went back and set boot to Launch CSM = Disabled, and it's still doing the same blue screen error as before. innaccessible boot device, then error 0x0000001
 
Okay — frustrating, but this INACCESSIBLE_BOOT_DEVICE BSOD usually means Windows can’t talk to the storage controller/driver at boot (not a licensing or edition problem). Since you’re in WinPE/Hiren’s and the disk layout is unchanged (Windows = E:, ESP = C, the next reasonable, low‑risk steps are:
  • 1) try the UEFI bcdboot repair (quick test), and if that doesn’t fix it
  • 2) enable the common storage drivers in the offline SYSTEM registry (non‑destructive) and then try boot again.
I’ll give exact commands to run in WinPE. Stop if you haven’t made a fresh Macrium image of Disk 0 (Samsung) since your last restore — do that now if you haven’t.
If you’re ready, run these in the WinPE command prompt (copy/paste each block and paste the outputs if anything errors). I’ll assume Windows partition is E: and the ESP is C: from your previous outputs — if list vol shows different letters, use those.
A — Quick test: try to install UEFI boot files to the ESP
1) (confirm volumes)
diskpart
list vol
exit
2) Try to copy UEFI boot files:
bcdboot E:\Windows /s C: /f UEFI
  • If output says “Boot files successfully created” — reboot to BIOS, set Boot Mode = UEFI (CSM disabled), make “Windows Boot Manager (Samsung …)” first, disable Secure Boot for first boot, and try to boot.
  • If bcdboot fails or you still get INACCESSIBLE_BOOT_DEVICE at boot, continue to B.
B — Ensure ESP is writable (only if bcdboot failed with Access denied)
diskpart
select disk 0
attributes disk clear readonly
select vol 2
format fs=fat32 quick label=ESP
assign letter=S
exit
Then:
bcdboot E:\Windows /s S: /f UEFI
If that succeeds, do the BIOS steps above and test boot. If it still fails or bcdboot succeeds but BIOS still bluescreens, proceed to C.
C — Enable storage drivers in the offline SYSTEM hive (common fix for INACCESSIBLE_BOOT_DEVICE)
This will set the Start value of key storage drivers to a bootable state. We’ll load the offline SYSTEM hive, locate the Current control set, then set Start=0 for a handful of storage drivers (storport, storahci, msahci, iaStorV, nvme). This is non‑destructive but advanced — I’ll show commands exactly.
1) Load the offline SYSTEM hive:
reg load HKLM\TEMP_SYSTEM E:\Windows\System32\config\SYSTEM
2) Find which ControlSet is current:
reg query HKLM\TEMP_SYSTEM\Select /v Current
The output shows a number (usually 1 or 2). If it’s 1 then the path you’ll change is HKLM\TEMP_SYSTEM\ControlSet001\… ; if it’s 2 use ControlSet002, etc. I’ll call that ControlSet below — replace 00X with the two digits from the Current value (e.g., 001 or 002).
3) Set Start=0 for the drivers (run each reg add line; replace 00X with your ControlSet number):
reg add "HKLM\TEMP_SYSTEM\ControlSet00X\Services\storport" /v Start /t REG_DWORD /d 0 /f
reg add "HKLM\TEMP_SYSTEM\ControlSet00X\Services\storahci" /v Start /t REG_DWORD /d 0 /f
reg add "HKLM\TEMP_SYSTEM\ControlSet00X\Services\msahci" /v Start /t REG_DWORD /d 0 /f
reg add "HKLM\TEMP_SYSTEM\ControlSet00X\Services\iaStorV" /v Start /t REG_DWORD /d 0 /f
reg add "HKLM\TEMP_SYSTEM\ControlSet00X\Services\nvme" /v Start /t REG_DWORD /d 0 /f
Notes:
  • If any of those keys don’t exist you’ll get an error for that key — that’s OK, just continue.
  • storport and nvme are important for NVMe controllers; storahci/msahci/iaStorV cover SATA/AHCI/RST cases.
4) Unload the hive:
reg unload HKLM\TEMP_SYSTEM
5) Now try to restore/refresh boot files and then reboot:
bcdboot E:\Windows /s S: /f UEFI (use S: if you assigned ESP earlier; otherwise use C
Reboot, set BIOS to UEFI (CSM disabled), Windows Boot Manager first, Secure Boot OFF and test.
D — If that still fails: write GPT headers (gdisk) and retry
If firmware refuses to boot even after bcdboot and driver enables, the disk table might still be MBR and the firmware is strict. The reliable path then is to run gdisk (non‑destructive) to write GPT headers, ensure the ESP exists, and run bcdboot again. I can walk you through gdisk step by step if needed.
E — If you want the fastest temporary route to desktop
If your immediate priority is to get to desktop now and you don’t care about UEFI, re‑enable Legacy/CSM in BIOS and run the Windows Repair CD Command Prompt commands:
bootrec /fixmbr
bootrec /fixboot
bootrec /scanos
bootrec /rebuildbcd
(or bcdboot E:\Windows)
That often gets an MBR image booting quickly — then we can convert to GPT properly afterward.
Which do you want to try now?
  • If you want to go straight for the least disruptive test: run the bcdboot E:\Windows /s C: /f UEFI command and paste the full output.
  • If that fails (or already did) and you’re comfortable with registry edits, I’ll guide you through the exact reg load / reg add sequence and we’ll enable the storage drivers (I’ll wait while you run them and check results).
Say which route and I’ll stay with you and interpret every output.