Invalid partition table - Windows Home 10 won't load

[Atyilu]

My computer fails to load the operation system when switching it on. On a black screen the error message shows: Invalid partition table

When attempting to launch the opsystem from a Windows .ISO DVD any options offered on the screen fail to work out, the single viable option is to use CMD . (Currently I can not create a bootable USB flash drive as my single Windows computer is broken down due to the above failure. )

Please assist me how to make use of the command line in order to reset the partition containing the operation system active again and to have a partition where it can boot from.

From the attached acreen shots it seems so, that all formerly existing partitions are sound and healthy. However, the separate partition formerly allocated for Windows ( label "E" , named as "Oprendszer" ) is not active and none of the partitions is marked as "boot" partition, according to the info section.

On screen shot 1 I wonder why the volume containing the operation system is not listed with its appr. 90 GB size, whereas on all other screen shots it is clearly shown. Can that refer to the cause of the malfunctioning ?

So what CMD commands can be used to make partition "E" active and bootable ?

( on the attached images partition "C" is the most important volume, that is first priority for me to remain sound and retrievable, containing personal content. It was accidentally renamed to C by the system, not me )

Additional info: before the above accident turned out I wanted to extend the recovery partition ( volume 2 on the screen shots) to 550 MB. Though that apparently has been realized, next time the op system could not boot in)

Thank you for your assistance.

 

[ChatGPT]

It appears your computer is experiencing an issue with the partition table, leading to the "Invalid partition table" error. You can resolve this issue using the Command Prompt from the Windows installation media. Here’s a step-by-step guide: Steps to Make the Partition Active Using DiskPart 1. Boot from Windows Installation Media: - Boot your computer using the Windows installation DVD. - On the initial setup screen, press Shift + F10 to open Command Prompt. 2. Open DiskPart: - Type diskpart and press Enter to start the DiskPart utility. 3. List Disks and Select the Correct Disk: - Type list disk to display all disks. - Select the disk where your Windows installation is located using:

 select disk 0

4. List Partitions and Select the Correct Partition: - Display all partitions in the selected disk by typing list partition. - Select the partition that should be active (your Windows partition) with:

 select partition 3

5. Set the Partition as Active: - Type the command to mark the partition as active:

 active

6. Exit DiskPart: - Type exit to leave DiskPart. Steps to Fix the Boot Configuration Data (BCD) 1. Rebuild the BCD Store: - In the Command Prompt, type the following commands to rebuild the BCD store:

 bootrec /fixmbr bootrec /fixboot bootrec /scanos bootrec /rebuildbcd

- Confirm any prompts that appear. 2. Restart Your Computer: - Close the Command Prompt and select the option to restart your computer from the Windows installation media. Verify Partition Health and Restart: - Ensure that the critical partitions (especially the one containing your operating system) are neither hidden nor corrupted. Use detail partition command within DiskPart to inspect each required partition. Example Commands Recap: - Start DiskPart:

 diskpart

- List all disks and select the target disk:

 list disk select disk 0

- List all partitions and select the target partition:

 list partition select partition 3 active

- Rebuild BCD store:

 bootrec /fixmbr bootrec /fixboot bootrec /scanos bootrec /rebuildbcd

If you still face issues or observe errors, provide any specific error messages or behavior so we can further assist. Good luck, and let us know if you need additional help!

 

[Atyilu]

Already tried all bcdedit ..... commands earlier, but it did not help.

When applying the above AI commands the following error messsage appears in response:

"The selected disk is not a fixed MBR disk. The ACTIVE command can only be used on a fixed MBR disk"

So how can I fix it ?

 

[Mike]

Stop playing games with all the partitions and use a VM.

 

[ChatGPT]

The error message, "The selected disk is not a fixed MBR disk. The ACTIVE command can only be used on a fixed MBR disk", tells us that the system disk is likely configured with GPT (GUID Partition Table) rather than MBR (Master Boot Record). The ACTIVE command in Diskpart doesn't apply to GPT disks because GPT relies on UEFI and the EFI System Partition (ESP) for booting rather than an "active" partition.

---

Steps to Resolve the "Invalid Partition Table" Error on a GPT Disk:​

To fix this issue, you'll need to ensure that your system is using the proper UEFI bootloader and the necessary files are intact on the EFI System Partition (ESP). Follow these steps:

---

1. Verify Boot Mode​

• Enter your BIOS/UEFI settings (usually by pressing F2, Del, or a similar key during boot).
• Ensure the system is set to boot in UEFI Mode, not Legacy/CSM mode. Switching to Legacy for a GPT disk can cause the "Invalid partition table" error.

---

2. Repair Boot Files​

1. Boot into your Windows Installation Media using a USB/DVD.
2. Select your language, then choose Repair your computer.
3. Navigate to:
   • Troubleshoot > Advanced Options > Command Prompt.
4. Run the following commands to rebuild the boot files:
   

   cmd diskpart list disk select disk 0 # Make sure to select your Windows installation disk list partition select partition X # Replace X with the EFI System Partition (ESP), typically around 100-512 MB in size assign letter=Z # Temporarily assign a drive letter to the ESP (e.g., Z) exit

5. Rebuild the UEFI bootloader:
   

   cmd bcdboot C:\Windows /s Z: /f UEFI

   • Replace C:\Windows with the path to your Windows installation if it’s on a different drive.
6. Remove the drive letter assignment (optional but recommended):
   

   cmd diskpart select partition X # Replace X with the ESP again remove letter=Z exit

7. Restart your computer.

---

3. Check and Fix Disk Structure​

To verify that the disk structure (GPT) is correct, you can use bootrec commands:

1. In the same Command Prompt from the steps above:
   

   cmd bootrec /fixmbr bootrec /fixboot bootrec /scanos bootrec /rebuildbcd

• If bootrec /fixboot gives Access Denied, skip that step, as it's usually a permissions issue with the ESP but not critical to rebuilding the boot loader.

---

4. Check EFI Partition​

Ensure the EFI System Partition (ESP) is intact:

• The ESP should contain critical boot files, usually inside a folder structure like:
  

   EFI\Microsoft\Boot\bootmgfw.efi

• If it's missing or corrupted, the bcdboot command above will recreate these files.

---

Diagnosis Questions​

1. Are you sure the system disk supports UEFI?: If the BIOS is incorrectly set to Legacy, errors like this happen.
2. Is the disk layout GPT rather than MBR?: Use diskpart > list disk to confirm. GPT disks will have an asterisk () in the *GPT column.

---

If these steps don't resolve your issue, let me know what happens after running the commands, and we can explore further options like resetting the boot partition or verifying hardware.