Convert dual boot disk into single OS

zbook said:

Please explain one versus the other for EFI.
create partition msr | Microsoft Docs
UEFI/GPT-based hard drive partitions | Microsoft Docs
Type | Microsoft Docs


Currently one computer with UEFI displayed the above message.
"This PC can't run Windows 10
We couldn't update the system reserved partition"

This is not MSR related. That error message is misleading - I have seen it in relation to issues with updating EFI partition but MS have not properly updated error messages from legacy bios days (crap programming).

cereberus said:

The MSR is a partition reserved for future use and to date has no functionality and if deleted, there is no impact at all.

Of course, one day MS might use it but it is easy to recreate using diskpart.

Martin, Microsoft seems to think differently:

A Microsoft Reserved partition is required on every gpt disk. The size of this partition depends on the total size of the gpt disk. The size of the gpt disk must be at least 32 MB to create a Microsoft Reserved partition.

This from page already linked here a couple of times: create partition msr | Microsoft Docs

Kari

Kari said:

Martin, Microsoft seems to think differently:



This from page already linked here a couple of times: create partition msr | Microsoft Docs

Kari

MS require it to be installed but it has no functionality. If you delete it, nothing is affected whatsoever. It is a purely artificial requirement.

zbook said:

This is an image of the Microsoft error message seen with UEFI:

As I said the error is misleading. Look at the EFI system partition - it is almost full. That is what is causing your problem. You need to extend size of it (easier said than done as the pesky MSR partition gets in the way).

You need to


1) shrink C drive by say 105 MB from left using Minitool partition wizard free

2) backup MSR only using Macrium Reflect

3) Extend size of EFI partition by 100 MB (slightly lower than space created above to avoid zone boundary issues)

4) recover MSR to space between EFI and C drive.

You could just delete MSR and not bother or recreate it using diskpart instead if you prefer.

UEFI only needs two partitions to run (EFI and C drive). On small devices, I used to delete the MSR and recovery partitions.

However, the recovery partition is needed now if you use Marium Reflect Free in WinRe mode rather than older WinPE mode. WinRe mode gives ability to make Macrium Reflect bakupsierwifi which is great feature.