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- Mar 14, 2023
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Short answer — don’t format Partition 3 (R
to FAT32. It contains recovery data and your disk is currently MBR (not GPT), so formatting it and copying EFI files won’t make the system boot in UEFI. The safer, correct path is to convert the disk to GPT so Windows has a proper EFI partition (mbr2gpt will create the EFI using the free ~727 MB), then enable UEFI/Secure Boot in firmware and rerun the in‑place repair. That is the recommended, single reliable fix.
Why (brief)
Important: back up any irreplaceable data before starting. This is normally safe but it modifies partition layout and boot configuration.
Pre-checks (run in elevated PowerShell) — paste results if you want me to confirm:
1) Confirm BitLocker status:
manage-bde -status C:
(If BitLocker is enabled, suspend protection before conversion: manage-bde -protectors -disable C
2) Confirm disk 0 is the Windows disk and has sufficient free space at end:
Get-Disk -Number 0 | Format-List Number,FriendlyName,PartitionStyle
Get-Partition -DiskNumber 0 | Format-Table PartitionNumber,DriveLetter,Size,Type,Offset -AutoSize
Then run validation (this does not change anything):
3) Validate mbr2gpt can convert:
mbr2gpt.exe /validate /allowFullOS
4) Convert (this will create EFI & MSR and update boot files):
mbr2gpt.exe /convert /allowFullOS
5) Reboot into UEFI/BIOS and change boot mode:
Get-Disk -Number 0 | Format-List Number,FriendlyName,PartitionStyle
Get-Partition -DiskNumber 0 | Format-Table PartitionNumber,DriveLetter,Size,Type -AutoSize
You should see PartitionStyle : GPT and an EFI System Partition (Type = System or EFI) ~100–300 MB.
7) Re-run the in‑place repair (setup.exe from your Rufus USB or the ISO). Setup should no longer complain about TPM/Secure Boot or “couldn’t update system reserved partition.”
If mbr2gpt validation fails or you prefer not to convert
A) Walk through the validation now (I’ll wait while you run mbr2gpt /validate /allowFullOS and paste the output), or
B) Proceed with the conversion now (I’ll wait while you run /convert), or
C) Stop here and do this tomorrow?
If A — run this in an elevated prompt and paste the output:
mbr2gpt.exe /validate /allowFullOS
I’ll read the validation output and confirm it’s safe to convert.
Why (brief)
- Your disk is MBR (Get-Disk shows PartitionStyle : MBR). UEFI + Secure Boot require GPT + an EFI System Partition (FAT32).
- Partition 3 (R
currently holds recovery files — formatting it will destroy those and may not fix the installer error because the system is MBR. - mbr2gpt will convert the disk to GPT in-place, create the EFI partition (it will use free space at the end of the disk), and update the boot configuration so Setup/Repair can update the system reserved / EFI area. It’s what Microsoft provides for this scenario.
Important: back up any irreplaceable data before starting. This is normally safe but it modifies partition layout and boot configuration.
Pre-checks (run in elevated PowerShell) — paste results if you want me to confirm:
1) Confirm BitLocker status:
manage-bde -status C:
(If BitLocker is enabled, suspend protection before conversion: manage-bde -protectors -disable C
2) Confirm disk 0 is the Windows disk and has sufficient free space at end:
Get-Disk -Number 0 | Format-List Number,FriendlyName,PartitionStyle
Get-Partition -DiskNumber 0 | Format-Table PartitionNumber,DriveLetter,Size,Type,Offset -AutoSize
Then run validation (this does not change anything):
3) Validate mbr2gpt can convert:
mbr2gpt.exe /validate /allowFullOS
- If it reports validation success, proceed. If it reports errors, paste the validation output and I’ll interpret.
4) Convert (this will create EFI & MSR and update boot files):
mbr2gpt.exe /convert /allowFullOS
- Wait for it to finish. It typically completes in a minute or two and reports success. Do not interrupt.
5) Reboot into UEFI/BIOS and change boot mode:
- Disable Legacy/CSM boot and set the system to UEFI boot.
- Enable TPM / fTPM / Intel PTT in the firmware (if available).
- Enable Secure Boot if you want (you can enable after confirming boot works). Save and exit.
Get-Disk -Number 0 | Format-List Number,FriendlyName,PartitionStyle
Get-Partition -DiskNumber 0 | Format-Table PartitionNumber,DriveLetter,Size,Type -AutoSize
You should see PartitionStyle : GPT and an EFI System Partition (Type = System or EFI) ~100–300 MB.
7) Re-run the in‑place repair (setup.exe from your Rufus USB or the ISO). Setup should no longer complain about TPM/Secure Boot or “couldn’t update system reserved partition.”
If mbr2gpt validation fails or you prefer not to convert
- Alternative A (more work): Use GParted from a boot USB to move/extend partitions so the System Reserved gets bigger — more risk and time. I can guide that, but it’s slower.
- Alternative B: Keep going with the Rufus-modded USB install path (some users can do in‑place repair using the modified installer) — if you still see SRP error you’ll still need to fix partition layout.
- mbr2gpt is designed to be safe and Microsoft supports it, but it modifies boot configuration — a backup is recommended.
- If BitLocker is enabled, suspend it before conversion.
- If validation reports “not enough space” or other issues, paste the validation output — I’ll interpret and give the exact next remedial step.
A) Walk through the validation now (I’ll wait while you run mbr2gpt /validate /allowFullOS and paste the output), or
B) Proceed with the conversion now (I’ll wait while you run /convert), or
C) Stop here and do this tomorrow?
If A — run this in an elevated prompt and paste the output:
mbr2gpt.exe /validate /allowFullOS
I’ll read the validation output and confirm it’s safe to convert.