Repair Install Windows 10 with an In-place Upgrade  

Will a repair installation install in GPT if the current windows installation is MBR?

Celeras said:

Will a repair installation install in GPT if the current windows installation is MBR?

No.

NavyLCDR said:

No.

Drats 😫 Thanks

Celeras said:

Drats �� Thanks

It's easy to convert. One method is this:
Convert Windows 10 from Legacy BIOS to UEFI without Data Loss

Another method is to backup the Windows partition to another drive using a program like Macrium Reflect. Reformat the original drive as GPT. Create an EFI system partition. Restore the Windows partition, then use the bcdboot command to write boot files to the EFI system partition.

NavyLCDR said:

It's easy to convert. One method is this:
Convert Windows 10 from Legacy BIOS to UEFI without Data Loss

Another method is to backup the Windows partition to another drive using a program like Macrium Reflect. Reformat the original drive as GPT. Create an EFI system partition. Restore the Windows partition, then use the bcdboot command to write boot files to the EFI system partition.

Thanks again. Yes I was looking into this but I hit a dead end, that's why I hoping for this alternative. MBR2GPT gives the following error when validating: ValidateLayout: First partition too close to the beginning of the disk. Should start at offset 17408 or above, found at 4096

I tried shrinking the first partition slightly (System Reserved) and moving it ahead of unallocated space to create the proper offset, and while that made it pass MBR2GPT validation as soon as I tried to convert I got an error. And after it failed then I couldn't boot at all. Had to restore my backup.

Is there a more detailed guide to the second method you outlined using Macrium? That's what I already use for my backups.

Celeras said:

Thanks again. Yes I was looking into this but I hit a dead end, that's why I hoping for this alternative. MBR2GPT gives the following error when validating: ValidateLayout: First partition too close to the beginning of the disk. Should start at offset 17408 or above, found at 4096

I tried shrinking the first partition slightly (System Reserved) and moving it ahead of unallocated space to create the proper offset, and while that made it pass MBR2GPT validation as soon as I tried to convert I got an error. And after it failed then I couldn't boot at all. Had to restore my backup.

Is there a more detailed guide to the second method you outlined using Macrium? That's what I already use for my backups.

After making the backup of your Windows partition (and any other date partitions you need to create), boot from the Macrum Refelct Rescue Drive and open a command prompt:

Code:

diskpart
list disk
select disk # <- select the drive number you want to convert
clean <- this will erase the disk selected above, make sure it is the drive you want to convert!
convert gpt
select part 1
delete part override
create part EFI size=100
format fs=fat32 quick
assign letter=k
create part MSR size=16
exit
exit

Then restore your Windows partition to the unallocated space on the disk and assign it a drive letter. Let's assume you assign drive letter L: to it, then go back into command prompt:

Code:

bcdboot L:\Windows /s K: /f UEFI
exit

Then it would probably be a good idea to run the Fix Windows boot problems utility found under the restore menu of the Macrium Reflect Rescue Drive just to be sure. Then reboot, make sure BIOS settings are set to boot from your converted drive in UEFI mode.

Worked like a charm. Probably should have asked sooner instead of wasting all day trying to fix the stupid tool by myself on Google Thanks!

Awesome! Glad it worked out for you!

Wow, 124 pages on this thread! I believe I was here 2 years ago, also seeking to convert from MBR to GPT. Windows updates could not longer be applied. The conversion tool MBR2GPT would not work. 2 or 3 weeks of research and failures. Finally someone, probably NavyLCDR, pointed me to Macrium Reflect. What a wonderful tool, and what great advice!