Deleted System Reserved Partition - Need to Re-Create

Move the C drive to the right using tool like minitool partition wizard free, then run mbr2gpt, and drive will be converted to UEFI GPT.

It is not essential to have a separate system reserved partition but you do need to have some unallocated space to left of C drive partition to run mbr2gpt.

As stated, you do not need a Recovery Partition. This is created whenever you do an Upgrade to the newest Windows Version. This partition is used to have Recovery files to roll back to the previous version of Windows if you don't like the new one or it is not working out for you. Once the short period has expired, this recovery partition is not needed and can be deleted with no problems.

Remember that if you can't upgrade to Windows 11 because your computer doesn't meet the minimum requirements, Windows 10 is supported until 2025.

It is tricky to convert the disk that has C: on it from MBR to GPT. Be sure you have a good backup before attempting. You cannot be booted into Windows while attempting this, you need to boot into WindowsPE, using a Rescue Boot Flash drive or a the Windows 10 Installer USB Flash drive where you can use the Command Prompt outside of Windows.

https://learn.microsoft.com/en-us/wi...ent/mbr-to-gpt

cereberus said:

Move the C drive to the right using tool like minitool partition wizard free, then run mbr2gpt, and drive will be converted to UEFI GPT.

It is not essential to have a separate system reserved partition but you do need to have some unallocated space to left of C drive partition to run mbr2gpt.

I just tested mbr2gpt - you do not even need to move C drive - you just need some unallocated space.

mbr2gpt will put efi to right of c drive. It does not actually matter though.


However, if you wish to reorder partitions, that is easily sorted by making image backup of drive after conversion, then restoring partitions one at a time (EFI), then C drive. Macrium Reflect can restore both at same time in correct order using drag and drop.

g50eed said:

Years ago I deleted the system reserved partition and reclaimed the space so everything is under one partition. I need to undo that somehow and re-create or restore or recover the system reserved partition (whatever the proper verb is). Is there a way to to that? I cannot convert to GPT without it and without GPT I cannot enable secure boot and cannot upgrade to Windows 11 before Windows 10 goes EOL.

For your case, it is really easy. I recommend making an image backup first.

1) Boot from a windows installation usb drive

2) press shift + f10 at first screen to get to command prompt

3) run following

Code:

mbr2gpt /validate /disk:0

4) Assuming that shows all is fine

Code:

mbr2gpt /convert /disk:0

5) set bios to boot in UEFI mode and reboot

@g50eed


The only two partitions you need to boot Windows (on a GPT disk) are these in the RED box...

Ghot said:

@g50eed


The only two partitions you need to boot Windows (on a GPT disk) are these in the RED box...

As OP only has one partition, winre.wim should be on C drive in hidden folder C:\Recovery.

cereberus said:

3) run following

Code:

mbr2gpt /validate /disk:0

That's the problem. mbr2gpt won't validate my C: drive because the OS partition is missing:

g50eed said:

cereberus said:

3) run following

Code:

mbr2gpt /validate /disk:0

That's the problem. mbr2gpt won't validate my C: drive because the OS partition is missing:

You have to do it from winpe as I said in first steps 1 and 2.

cereberus said:

You have to do it from winpe as I said in first steps 1 and 2.

I created the WinPE bootable media. Question: Is using mbr2gpt within WinPE non-destructible like within Windows 10?