Convert Windows 10 from Legacy BIOS to UEFI without Data Loss  

steve108 said:

Nothing wrong with waiting for a second opinion.

In the mean time, if you haven't see this: Enable or Disable Windows Recovery Environment in Windows 10

Thanks. Going to read that. It is possible I disabled that 'feature' with WinAero Tweaker.

Here's a second opinion for you : Need Help with MBR2GPT Feel free to wait for a third.

steve108 said:

Here's a second opinion for you : Need Help with MBR2GPT Feel free to wait for a third.

reagentc /enable
REAGENTC.EXE: Unable to update Boot Configuration Data.

(Yes it is run in an elevated command prompt)

Krawk said:

reagentc /enable
REAGENTC.EXE: Unable to update Boot Configuration Data.

I would try that after you switched BIOS to UEFI and booted to Windows from the boot drive.

Also please do this: How to Post a Screenshot of Disk Management

steve108 said:

I would try that after you switched BIOS to UEFI and booted to Windows from the boot drive.

Also please do this: How to Post a Screenshot of Disk Management

UEFI Enable Success. Boot Success.
REAGENT enable success.
Posting my drive layout now. Is it normal for the extra partition to have a drive letter now? (H: in this example)

Krawk said:

Thanks. Giving it a bit of time before I do so in case a second opinion chimes in but I do trust you! I know WinRE is the Recovery Environment.
In the thread about being unable to create a recovery drive, I've seen many people saying that the RE is less important in Windows 10.

This process has created a 4th 100Mb partition for the EFI.

Well, let's say that it isn't safe to reboot now. What are you going to do? Hope the computer never reboots? You don't have much choice.

Krawk said:

UEFI Enable Success. Boot Success.
REAGENT enable success.
Posting my drive layout now. Is it normal for the extra partition to have a drive letter now? (H: in this example)

Yes it is normal. And yes you can remove the drive letter altogether. You can remove the drive letter by right clicking in disk management and removing it there or:

Code:

diskpart
select vol H
remove
exit
exit

NavyLCDR said:

Yes it is normal. And yes you can remove the drive letter altogether. You can remove the drive letter by right clicking in disk management and removing it there or:

Code:

diskpart
select vol H
remove
exit
exit

Why didn't the screenshot show EFI system partition? Is it because the partition had a drive letter assigned?

Wait ..... There's already a 100 MB EFI partition and a 557 MB recovery partition. So what is H: ?

steve108 said:

Why didn't the screenshot show EFI system partition? Is it because the partition had a drive letter assigned?

Wait ..... There's already a 100 MB EFI partition and a 557 MB recovery partition. So what is H: ?

H: is more than likely the original legacy BIOS system reserved partition.

NavyLCDR said:

H: is more than likely the original legacy BIOS system reserved partition.

Thanks you. So it could be theoretically deleted as it's not needed for UEFI, but best to leave it alone - you'd probably suggest?

@Krawk,
"The default partition layout for UEFI-based PC" I like the diagram in here:
https://docs.microsoft.com/en-us/win...iew=windows-10

Note that you won't see the MSR partition in Disk Management - you can see it from diskpart.