I'm currently running Windows 11 Pro 23H2 (22631.6199), and I've had problems updating to 24/25H2. I've tried updating from the windows updater, as well as from the bootable media. I currently get the following error: 0xC1900101 - 0x20017The installation failed in the SAFE_OS phase with an error during BOOT operation. I've exhausted virtually all solutions that I've found online, including the following: Activating SecureBoot Resolving driver conflicts Running sfc /scannow Running DISM /Online /Cleanup-Image /RestoreHealth Updating BIOS, etc. And many other solutions. While attempting these, there were a few references to reagentc - disabling and re-enabling it. This is where I noticed a problem, and I believe it's what's blocking the update. Running reagentc /info shows it as disabled: Attempting to enable it says that it's successful, but it's still disabled. I've tried replacing the winre.wim file and the reagent.xml file from the update image (adding them to C:\Windows\System32\Recovery ) - and enabling after that does remove the files - but everything still shows as disabled. I then recalled that I actually cloned my old windows drive to the current SSD its on - and noticed that I had 2 recovery partitions, and 2 system partitions. After a lot of experimenting, I deleted both recovery partitions and recreated a single recovery partition - but that still did not work: I'm honestly at my wits end with this, and would appreciate any help. Running reagentc /enable is doing something , but I've no idea what windows thinks my recovery partition is, or why it isn't enabling. Any advice or assistance is greatly appreciated.

Please open Disk Management and maximize it. Adjust the column widths in the top pane to make all the entries visible. Post a screenshot. Open the admin Command Prompt and run these commands: bcdedit reagentc /info dir c:\windows\system32\recovery /a dir c:\recovery\WindowsRE /a diskpart list disk select disk 0 list part list vol exit Post the output.

Windows 11 Update 25H2 Error and WinRE Problems

Alex R 65

I'm currently running Windows 11 Pro 23H2 (22631.6199), and I've had problems updating to 24/25H2. I've tried updating from the windows updater, as well as from the bootable media. I currently get the following error:

Windows 11 Setup 0xC1900101 - 0x20017The installation failed in the SAFE_OS phase with an error during BOOT operation.

I've exhausted virtually all solutions that I've found online, including the following:

Activating SecureBoot
Resolving driver conflicts
Running sfc /scannow
Running DISM /Online /Cleanup-Image /RestoreHealth
Updating BIOS, etc.
And many other solutions.

While attempting these, there were a few references to reagentc - disabling and re-enabling it. This is where I noticed a problem, and I believe it's what's blocking the update.

Running reagentc /info shows it as disabled:

User's image

Attempting to enable it says that it's successful, but it's still disabled.

User's image

I've tried replacing the winre.wim file and the reagent.xml file from the update image (adding them to C:\Windows\System32\Recovery) - and enabling after that does remove the files - but everything still shows as disabled.

I then recalled that I actually cloned my old windows drive to the current SSD its on - and noticed that I had 2 recovery partitions, and 2 system partitions. After a lot of experimenting, I deleted both recovery partitions and recreated a single recovery partition - but that still did not work:

User's image

I'm honestly at my wits end with this, and would appreciate any help. Running reagentc /enable is doing something, but I've no idea what windows thinks my recovery partition is, or why it isn't enabling. Any advice or assistance is greatly appreciated.

0 comments

Answer accepted by question author

Ramesh 183.6K Volunteer Moderator

Please boot into Windows.

Post the latest Disk Management screenshot.

Alex R 65 Reputation points

2026-01-12T13:40:50.4333333+00:00
Ramesh 183.6K Reputation points Volunteer Moderator

2026-01-12T13:47:13.48+00:00
Still not good. Now C is acting as the system partition. Perhaps someone copied the EFI folder there.

Please create a **FAT32 **partition in the following space:

Format it as FAT32 and assign the drive letter Y.

Run:

diskpart select disk 1 select part 1 set id=c12a7328-f81f-11d2-ba4b-00a0c93ec93b override gpt attributes=0x8000000000000000 assign letter=Y list part list vol exit bcdboot c:\windows /s Y:
Ramesh 183.6K Reputation points Volunteer Moderator

2026-01-12T13:56:42.42+00:00

Also, run msinfo32 and click System Summary.

Post a screenshot.
Alex R 65 Reputation points

2026-01-12T13:56:49.5233333+00:00
Ramesh 183.6K Reputation points Volunteer Moderator

2026-01-12T13:57:51.3133333+00:00

I didn't post those commands. Where did you get that from?

Alex R 65

In this comment - it seems like that should be part 4, not part 1 - since part 1 is the main OS partition.

diskpart
select disk 1
select part 1
set id=c12a7328-f81f-11d2-ba4b-00a0c93ec93b override
gpt attributes=0x8000000000000000
assign letter=Y
list part
list vol
exit
bcdboot c:\windows /s Y:

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Ramesh 183.6K Reputation points Volunteer Moderator

2026-01-12T14:02:30.2966667+00:00

Please post the latest Disk Management screenshot.
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Alex R 65 Reputation points

2026-01-12T14:04:22.8933333+00:00

I did create the FAT32 partition - which ended up being 99MB. It's in the first slot in disk management, but listed as part 4 in diskpart:
Ramesh 183.6K Reputation points Volunteer Moderator

2026-01-12T14:06:06.41+00:00

Gotcha. Maybe it's a good idea to post a screenshot of Disk Management after a reboot.

Edit: By "Gotcha", I meant "I understand". It can sometimes convey a different meaning.
Ramesh 183.6K Reputation points Volunteer Moderator

2026-01-12T14:19:25.37+00:00

The next steps will be:

To create the EFI partition

Remove the EFI partition located at the end of the drive.

Remove the boot folder in the C drive. This has to be done via WinRE (USB boot).

Once done, enable WinRE.
Alex R 65 Reputation points

2026-01-12T14:50:40.6133333+00:00

boot.txt

After a restart, it was part 1. Followed the commands above
Ramesh 183.6K Reputation points Volunteer Moderator

2026-01-12T14:53:12.9833333+00:00

The commands ran fine.

Can you open msinfo32.exe and check the boot mode?

It should read UEFI.
Ramesh 183.6K Reputation points Volunteer Moderator

2026-01-12T14:55:43.3366667+00:00
Run:

diskpart disk 1 select part 4 set id=ebd0a0a2-b9e5-4433-87c0-68b6b72699c7 gpt attributes=0x0000000000000000 exit

Now, you should be able to delete the EFI partition at the end of Disk 1. Please do so.
Alex R 65 Reputation points

2026-01-12T14:56:10.3666667+00:00

Sorry - yes, it's UEFI:
Alex R 65 Reputation points

2026-01-12T14:57:38.17+00:00

Partition deleted
Ramesh 183.6K Reputation points Volunteer Moderator

2026-01-12T15:00:26.66+00:00
Great. Please boot into WinRE using the USB disk.

In WinRE Command Prompt, run:

bcdedit | find "osdevice"

In the output, note the drive letter for the OS partition.

Suppose it's D:\

Run:

attrib -s -h -r D:\EFI ren D:\EFI D:\Unused.EFI wpeutil reboot

(If you get any errors, please mention them here.)

Boot into Windows and post the latest Disk Management screenshot.
Alex R 65 Reputation points

2026-01-12T15:57:18.39+00:00

I'm getting this when running bcdedit from the command line:
The boot configuration data store could not be opened.

The requested system device cannot be found.

Though checking the volumes, it is assigned D:
Ramesh 183.6K Reputation points Volunteer Moderator

2026-01-12T16:13:55.7266667+00:00
Let's see if the drive letter Y is intact.

Run:

diskpart list vol exit
Alex R 65 Reputation points

2026-01-12T16:17:05.38+00:00
Ramesh 183.6K Reputation points Volunteer Moderator

2026-01-12T16:21:02.84+00:00
Run:

select volume 2 assign letter=y list vol exit bcdboot d:\windows /s Y: /f ALL dir Y:\BCD /s /a
Alex R 65 Reputation points

2026-01-12T16:24:57.07+00:00
Ramesh 183.6K Reputation points Volunteer Moderator

2026-01-12T16:27:11.4566667+00:00
Let's rename the EFI folder on the OS drive. (If Windows doesn't boot, we may need to revert the change later.)

Run:

attrib -s -h -r D:\EFI attrib -s -h -r D:\Boot ren D:\EFI Unused.EFI ren D:\Boot Unused.Boot wpeutil reboot

(If you get any errors, please mention them here.)

Boot into Windows and post the latest Disk Management screenshot.
Ramesh 183.6K Reputation points Volunteer Moderator

2026-01-12T16:28:14.9566667+00:00

I've modified the 3rd command. Please refresh this page.
Alex R 65 Reputation points

2026-01-12T16:37:42.5466667+00:00
Ramesh 183.6K Reputation points Volunteer Moderator

2026-01-12T16:39:01.6566667+00:00
Very good.

Please run:

bcdedit reagentc /disable reagentc /enable reagentc /info
Alex R 65 Reputation points

2026-01-12T16:40:37.85+00:00

Lovely!
Ramesh 183.6K Reputation points Volunteer Moderator

2026-01-12T16:45:42.67+00:00

Great. WinRE is sorted. Unfortunately, I skipped checking the Disk Management screenshot (in your original post) earlier. Only noticed the problem in the full Disk Management screenshot posted today.

If you want to merge the free space next to the Recovery partition, let me know.

If this also fixes the 0xC1900101 error, that will be great.
Alex R 65 Reputation points

2026-01-12T16:49:20.02+00:00

I'll be able to handle merging the unused space back in myself - have recreated the recovery partition before, so I'm not too worried about that (and it's only a few hundred megs anyway).

I'll test updating again tomorrow - hopefully this has fixed the issue. Thanks for all your help so far!
Ramesh 183.6K Reputation points Volunteer Moderator

2026-01-12T16:51:07.4+00:00

Good luck and keep me posted.

Thanks for all your help so far!

You're welcome.
Alex R 65 Reputation points

2026-01-13T10:56:11.8+00:00

Updated this morning, and everything went smoothly. Looks like the WinRE issue was the culprit in this case.

Thanks for your help!
Ramesh 183.6K Reputation points Volunteer Moderator

2026-01-13T10:59:52.09+00:00

Excellent. Duly noted. Henceforth, one must check the EFI partition for 0xC1900101 - 0x20017 issues. WinRE wasn't the problem because it's not boot-critical. The EFI partition was the issue.

Thanks for the feedback!

Answer accepted by question author

Ramesh 183.6K Volunteer Moderator

No wonder you were unable to enable WinRE. The problem here is the system is booting from the System Reserved partition instead of the EFI partition.

Please boot into Windows RE using the Windows 11 USB setup disk. We have to fix the boot partitions.

In WinRE Command Prompt, type the following commands:

diskpart

select disk 1

list part

list vol

Exit

Take a photo of the output screen and upload the image(s) here.

Don't quit WinRE yet. Some more commands need to be run.

Ramesh 183.6K Reputation points Volunteer Moderator

2026-01-12T13:04:35.97+00:00

Note:

Here's how to create the USB setup disk.

Create installation media for Windows - Microsoft Support

Windows Recovery Environment - Microsoft Support

How to access Windows Recovery Environment (WinRE)
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This comment has been deleted due to a violation of our Code of Conduct. The comment was manually reported or identified through automated detection before action was taken. Please refer to our Code of Conduct for more information.
Alex R 65 Reputation points

2026-01-12T13:10:45.79+00:00

Ramesh 183.6K Volunteer Moderator

Run:

select disk 1
select part 1
del part override
create partition efi size=100
format fs=fat32 quick
assign letter=Y
list vol

Post the screenshot.

Alex R 65 Reputation points

2026-01-12T13:20:18.7366667+00:00
Ramesh 183.6K Reputation points Volunteer Moderator

2026-01-12T13:22:01.9333333+00:00
Run:

select disk 1 list part exit
Alex R 65 Reputation points

2026-01-12T13:24:22.4166667+00:00

Ramesh 183.6K Volunteer Moderator

Run:

bcdboot d:\windows /s Y:
diskpart
select disk 1
select part 4
del part override
select volume Y
remove
exit

Ramesh 183.6K Reputation points Volunteer Moderator

2026-01-12T13:27:44.3+00:00

Note: It appears you didn't exit from diskpart. Please exit diskpart before running the latest commands.
Alex R 65 Reputation points

2026-01-12T13:30:53.3933333+00:00

4 additional answers

Ramesh 183.6K Reputation points Volunteer Moderator

2026-01-12T12:23:41.54+00:00
Please open Disk Management and maximize it. Adjust the column widths in the top pane to make all the entries visible. Post a screenshot.

Open the admin Command Prompt and run these commands:
```
bcdedit
reagentc /info
dir c:\windows\system32\recovery /a
dir c:\recovery\WindowsRE /a
diskpart
list disk
select disk 0
list part
list vol
exit
```
Post the output.
Was this answer helpful?
Alex R 65 Reputation points

2026-01-12T12:30:14.98+00:00

bcdedit.txt

I listed disk 1 instead of 0, since that's the OS disk with the recovery/boot partitions.
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Windows 11 Update 25H2 Error and WinRE Problems

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