Another mbr2gpt error - Disk layout validation failed for disk 1

Originally, I used mbr2gpt and got an error:

Cannot find OS partition(s) for disk 0

I looked at Disk Management and found that Disk 0 is an HDD which I use for backups; it is not the boot disk. The boot disk was Disk 4 and is an SSD.

Disk 0 is not only listed as "Active" but it also is listed as "System."

I tried

Code:

mbr2gpt /validate /disk:4

but received the error in the title.

I marked Disk 4 as "Active." I restarted my computer and it would not boot, so I set Disk 4 as "inactive." It boots just fine after that.

I used

Code:

reagentc /enable

but still got the above errors.

I unplugged all of the drives except the boot drive (i.e., Disk 4 which then became Disk 0). The computer would not boot.

I used

Code:

mbr2gpt /validate /disk:0

after unplugging all superfluous disks while in Windows Repair. Could not validate.

I also tried to fix the booting problem with Windows 10 "Advanced" options. Did not work.

I reconnected the original Disk 0 and it is again Disk 0 with the Boot Disk as Disk 1. My computer now boots fine, but I still get the error in the title when I use

Code:

mbr2gpt /validate /disk:1 /allowFullOS

I know the problem is that the System is on one drive and the Boot stuff is on another, but I do not know how to get the System and Boot disk on the same Disk.

Any ideas as to what I need to do to get mbr2gpt to validate without errors?

Thank you for any help you might provide.

P.S. For some reason, I cannot get any options when I right-click on the Disks in Disk Management. Weird.

Thank you, @Megahertz. This worked and I now have Win 11 installed.

Good.

Did you created a System partition or it wasn't needed?

@Megahertz - I did not intentionally create a System partition, but such a partition was created for me at some point.