Windows Server 2016 - Extend C: Drive Without Third-Party Tools (EFI Partition Between C: and Unallocated Space)

Question

We have a Windows Server 2016 VM with the following GPT partition layout:

Recovery Partition 500 MB

C: Drive ~79 GB

EFI System Partition 100 MB

Unallocated Space 11 GB

The issue is that the 100 MB EFI System Partition is located between the C: drive and the unallocated space.

Our objective is to extend the C: drive to support an OS upgrade, as the current free space may not be sufficient and the maintenance window is limited.

We would like to avoid using any third-party partition management tools.

Questions:

1. Is there a Microsoft-supported method to extend the C: drive in this scenario without using third-party tools?
2. Is it safe to delete and recreate the 100 MB EFI partition elsewhere on the disk without impacting the operating system?
3. If recreating the EFI partition is the recommended approach, what are the supported steps to:
   • Create a new EFI partition
     • Rebuild the boot files
       • Validate that the server boots correctly
         • Remove the old EFI partition
           • Extend the C: drive
4. Is there any alternative method that would allow the C: drive to be extended without modifying the EFI partition?

Any Microsoft-supported guidance or documentation would be greatly appreciated.

Answer 1

You can convert the 500 MB Recovery partition to an EFI partition.

Then delete the 100 MB EFI partition and merge the free space with C.

From Command Prompt (admin), please run these commands:

reagentc /info

dir c:\windows\system32\recovery /a

diskpart

select disk 0

list part

list vol

exit

Post the output here.

Answer 2

Hii,

In this case, I wouldn't recommend using the method to recreate the EFI partition, as your Windows might fail to boot.

If you need to increase EFI space to update, try the procedure below:

Search for cmd. Press-and-hold or right-click on Command Prompt in the results, and select Run as administrator.

At the command prompt, type mountvol y: /s and then hit Enter. This will add the Y: drive letter to access the System Partition.

Switch to the Y drive by typing Y: and press Enter. Then, navigate to the Fonts folder by typing cd EFI\Microsoft\Boot\Fonts. Once there, type del . to delete font files. The system may ask you if you are sure to continue, press Y and then Enter to continue.

Credits: https://learn.microsoft.com/en-us/answers/questions/3953657/windows-11-version-24h2-not-updating?forum=windows-windows_11-wintop_update&referrer=answers

Please consider rating the question (accepting the answer or not) and visiting the Microsoft Q&A community if you have further questions.

Thanks.