Why does BitLocker want to resize my OS partition when it already has the required partitions?

Question

I have a working Windows 10 installation with the following partitions:

260MB EFI System Partition
16MB MSR Partition
200GB OS Partition (BitLocker encrypted)
275GB Data Partition (BitLocker encrypted)
1000MB Windows Recovery Partition

When booting, F10 successfully loads the Windows Recovery environment.

Now, I tried to perform a fresh install of Windows 11. To do this, I am prompted to suspend BitLocker on the OS partition. Once this is done, I'm able to continue with the setup and choose the C partition to format and install Windows 11 on.

Unfortunately, once installed I am not able to enable BitLocker again without the message that the OS partition needs to be shrunk and yet another recovery partition created.

Why is this happening or how do I stop it? Keep in mind BitLocker was working under Windows 10 AND works in Windows 11 if I do an upgrade via Windows Update instead of a clean install. In that case, I can decrypt, turn off and re-enable BitLocker and it's quite happy not to shrink or create any new partitions.

What magic combination of steps do I need to perform to keep my existing partition table AND enable BitLocker on a fresh Windows 11 install?

I want to keep this partition table like I have it, because if I mess with it, the F10 recovery environment doesn't work.

Thanks
Jamie

Answer 1

@Docs

When I remove all partitions during Windows setup and allow them to be created automatically, I do get a WinRE partition, and BitLocker activates without creating any extra partitions, but the Lenovo F10 (actually, I think it's F11) key no longer works.

The only way to have that working, is to keep that WinRE partition (the default created by Lenovo).

I decided in the end not to bother with trying to make the F key work to boot in to the environment and instead just allow Windows to create what it wants during setup.

Thanks for your help
Jamie

Answer 2

With Macrium you can perform trial and error steps.

This is a trial and error step:

Open administrative command prompt and type or copy and paste:

reagentc /info
reagentc /disable

Then modify only the C: partition.

Open administrative command prompt and type or copy and paste:

reagentc /info
reagentc /enable

Did you lose the F10 method with recreating the recovery partition too?

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Answer 3

@Docs Thank you for the reply. I have been using Macrium so that I can keep trying different scenarios.

Although allowing Windows to create the default partition scheme works, it breaks the Lenovo F10 boot feature, which I wanted to keep in place.

Answer 4

1) This link may be useful to boot to Windows Recovery Environment (RE):

https://www.elevenforum.com/t/boot-to-advanced-startup-winre-in-windows-11.425/

2) Free backup images can be made and restored which allow trial and error testing.
(save the backup images to another disk drive or the cloud as needed)

(Acronis, Aoemi, EaseUS, Macrium, Paragon, etc.)

3)When performing a clean install of Windows 11 delete all partitions and allow the Windows Media Creation Tool (MCT) (Windows 11 iso) to create all of the default partitions.

a) Boot to the MCT

b) Delete all partitions making an unallocated disk drive

c) Clean install Windows 11

https://www.elevenforum.com/t/clean-install-windows-11.99/

One or more of these links may be useful:

https://learn.microsoft.com/en-us/windows-hardware/manufacture/desktop/configure-uefigpt-based-hard-drive-partitions?view=windows-11

https://learn.microsoft.com/en-us/windows/security/information-protection/bitlocker/bitlocker-recovery-guide-plan

https://support.microsoft.com/en-us/windows/back-up-your-bitlocker-recovery-key-e63607b4-77fb-4ad3-8022-d6dc428fbd0d

https://learn.microsoft.com/en-us/windows/security/information-protection/bitlocker/bitlocker-overview

https://learn.microsoft.com/en-us/windows/security/information-protection/bitlocker/bitlocker-key-management-faq

https://learn.microsoft.com/en-us/windows/security/information-protection/bitlocker/bitlocker-recovery-guide-plan?source=recommendations

https://learn.microsoft.com/en-us/windows/security/information-protection/bitlocker/bitlocker-device-encryption-overview-windows-10?source=recommendations

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