Windows 10: Win 10 "losing" boot partition - assigning wrong letter - can't boot

Hi all -

New to this forum - 1st post

My machine is a rather interesting triple-boot box (Win 10 Pro version 1903, Ubuntu Linux 18.04, and MacOS Catalina).
Booting via UEFI. Boot manager is Clover, with GRUB secondary for Linux. Windows and Linux boot from one NvMe drive and MacOS from another. Each boot drive has its own EFI partition. There are also four other SSD drives and one spinner drive.

All has been working fine for quite some time, through multiple OS updates and hardware tweaks and upgrades.

However, recently Win10 has failed to boot, going directly to automatic repair, which fails; diagnosis fails.

Linux and MacOS continue to boot normally.

When I go into Command Prompt through Advanced options in recovery, DISKPART shows that the letter order of the partitions has been scrambled, with the Windows boot partition no longer being assigned C:. It's been assigned D: E: F: and others.

Changing the drive letters via DISKPART does not solve the problem.
BCDEDIT | find "osdevice" finds the correct partition.

However, BOOTREC /rebuildbcd does NOT find any identified Windows installations (perhaps this is because the drives are GPT-partitioned rather than MBR??)

CHKDSK /f on the boot partition -> clean.

I restored the boot partition from a cloned copy made last week - which was working at the time - no difference, same behavior.

Any thoughts? This is driving me nuts.

Thanks in advance.
Bob

:)

 

Win 10 "losing" boot partition - assigning wrong letter - can't boot

Bob,

When you boot into any recovery environment [including from the USB], you are in a different OS and it assigns drive letters according to its own rules. Those drive letters are used only while that temporary OS is in use. As soon as you are back in normal Windows your drive letters will be decided by Windows again so you'll be back to the drive with Windows on it being C:\. You do not need to take any action about this matter.

If you were activated before then the MS servers will recognise your computer when you go back online afterwards and will activate you again. There is no need for any product key or indeed any action on your part - during any reinstallation you just skip the product key step.

System restore points are only marginally more usefu than chocolate teapots. Put your faith in system images instead.

Denis

 

Win 10 "losing" boot partition - assigning wrong letter - can't boot

Hi all -

New to this forum - 1st post

My machine is a rather interesting triple-boot box (Win 10 Pro version 1903, Ubuntu Linux 18.04, and MacOS Catalina).
Booting via UEFI. Boot manager is Clover, with GRUB secondary for Linux. Windows and Linux boot from one NvMe drive and MacOS from another. Each boot drive has its own EFI partition. There are also four other SSD drives and one spinner drive.

All has been working fine for quite some time, through multiple OS updates and hardware tweaks and upgrades.

However, recently Win10 has failed to boot, going directly to automatic repair, which fails; diagnosis fails.

Linux and MacOS continue to boot normally.

When I go into Command Prompt through Advanced options in recovery, DISKPART shows that the letter order of the partitions has been scrambled, with the Windows boot partition no longer being assigned C:. It's been assigned D: E: F: and others.

Changing the drive letters via DISKPART does not solve the problem.
BCDEDIT | find "osdevice" finds the correct partition.

However, BOOTREC /rebuildbcd does NOT find any identified Windows installations (perhaps this is because the drives are GPT-partitioned rather than MBR??)

CHKDSK /f on the boot partition -> clean.

I restored the boot partition from a cloned copy made last week - which was working at the time - no difference, same behavior.

Any thoughts? This is driving me nuts.

Thanks in advance.
Bob

 

Win 10 "losing" boot partition - assigning wrong letter - can't boot

Hi, Spunk -
Per their website, EasyBCD can't fix a non-bootable Windows install - apparently it's only for bootloader management. However, they're happy to sell you something called EasyRE for $20-40 ;-)

- - - Updated - - -

Denis - thanks very much for the comeback. Much appreciated. Yes, agreed, chocolate teapots are not very functional!