MBR2GPT "Disk layout validation failed for disk 2"

Question

I am working on getting to windows 11, before support is over. While updating, I need to enable secure boot, and turn csm off. However, MBR2GPT will not validate my system drive. Attached are screenshots of everything I belive is useful. For the record, disk 0 is NOT the system drive, just and old drive that will be cleared once I remove important data that I need from it. This is a week old windows installation.

Answer 1

Step 1: Please run command prompt as an administrator and enter

bcdboot C:\Windows /s C:

Do not continue unless bcdboot reports success.

Step 2: Mark drive C as active in disk management.

Step 3: Mark drive D as inactive:

diskpart
select volume D
inactive

Do not mark drive D as inactive unless steps 1 and 2 have succeeded.

Step 4: Reboot.

Answer 2

Thanks for the details, Dudecool_e. 

Based on what you described and the screenshots, it looks like MBR2GPT is failing the disk layout validation because the system drive (Disk 2) doesn't meet one or more of its conversion requirements.

Here are the most common reasons this happens:

1. Too many partitions: MBR2GPT only supports up to 3 primary partitions on the disk before conversion. If there are more, it will fail.
2. Unsupported partition types: If there's a recovery or OEM partition that MBR2GPT doesn't recognize, it might block the conversion.
3. Disk not marked as system: Even though Disk 2 is your actual system drive, MBR2GPT needs to see the boot files on it. If the boot files are on another disk (like Disk 0), it won’t work.
4. Disk not set as active: The system partition must be marked as active in MBR. Run diskpart to confirm if the drives and partitions are in MBR. 

I have done the conversion many times on my PCs. Technically the boot files used by your OS is coming from Disk 0, in which you need to create a boot partition manually unto the drive C. Then, what I did is to run checkdisk, checkntfs, cleanmgr, perform optimization/TRIM first and proceed to MBR2GPT. It's better to disconnect the non-OS drives first, then do again the conversion. Let me know if it works or not.