How to fix Windows 11 25H2 installing update error 0xc1900201 ?

Reyansh Sharma 40 Reputation points
2026-05-25T05:32:56.2966667+00:00

I am trying to update my new laptop to Windows 11 version 25H2, but the update keeps failing. The error message says: “We couldn’t update the system reserved partition.”

I already tried the Windows Update troubleshooter, restarting the laptop, and running SFC/DISM scans.

Please help me fix the Windows Update problem safely without losing files or changing partitions manually.Screenshot 2026-05-25 110138

Windows for home | Windows 10 | Install and upgrade
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Answer accepted by question author
Ramesh 181.9K Reputation points Volunteer Moderator
2026-05-28T17:19:35.9266667+00:00

Please open an admin Command Prompt window (instead of PowerShell) and run these commands one by one:

mountvol Y: /s

del  /q  Y:\EFI\Microsoft\Boot\Fonts\*.ttf

powershell -command "GCI Y:\  -File -Recurse | Sort Length -descending | Select FullName, Length, Mode -first 10"

dir Y:\

Post the output here.

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AI answer

2026-05-25T05:33:22.2+00:00

Use only supported, non-destructive repair steps and advanced Windows Update troubleshooting. Do not manually resize or edit partitions.

  1. Run Windows Update Troubleshooter again
    • Select Start > Settings > System > Troubleshoot > Other troubleshooters.
    • Under Most frequent, select Windows Update > Run.
    • Let it complete, then restart the device.
    • After restart, go to Start > Settings > Windows Update > Check for updates and try installing Windows 11 25H2 again.
  2. Repair Windows Update components These steps are safe for files and partitions.
    1. Rename SoftwareDistribution and Catroot2 folders
    • Open Command Prompt as administrator.
    • Run these commands one by one, pressing Enter after each and waiting for completion: 
           net stop bits
     net stop wuauserv
     ren %systemroot%\softwaredistribution softwaredistribution.bak
     ren %systemroot%\system32\catroot2 catroot2.bak
     net start bits
     net start wuauserv
    • Close Command Prompt and restart the computer.
    • Try Windows Update again.
    1. Use DISM and SFC to repair component store
    • Open Command Prompt as administrator.
    • Run: 
           DISM.exe /Online /Cleanup-image /Restorehealth
    • Wait for it to finish (can take several minutes).
    • Then run: 
           sfc /scannow
    • After both complete, close Command Prompt and run Windows Update again.
  3. Check for other common upgrade blockers Follow the general, non-destructive fixes for Windows 11 upgrades:
    • Remove nonessential external hardware (USB drives, external HDDs, printers, docks).
    • Make sure all important updates and drivers are installed in Windows Update.
    • Temporarily uninstall non-Microsoft antivirus or security software from Control Panel > Programs > Programs and Features and restart.
    • Uninstall old or nonessential apps that might interfere with setup, then retry the upgrade.
  4. Advanced checks (optional but safe)
    • Temporarily remove third-party security software if still installed, then try the update.
    • Check and repair disk errors:
      • Open Command Prompt as administrator.
      • Run: 
               chkdsk /f C:
      • Approve running on next restart if prompted, then restart.
      • After disk check completes, retry Windows Update.

If the update continues to fail after these steps, collect the exact error text and code from Settings > Windows Update > Update history and contact Microsoft support as indicated in the upgrade error documentation.

References:

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  1. DaveM121 935.7K Reputation points Independent Advisor
    2026-05-25T06:09:00.0333333+00:00

    Before providing you with a solution, I need some information about your system.

    1

    Click your Start Button, type winver and hit Enter

    Please provide a screenshot of the resulting dialog.

    2

    Right click your Start Button and open Disk Management.

    Please provide a screenshot of that window showing all drives and partitions in the bottom pane.

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  2. Reyansh Sharma 40 Reputation points
    2026-05-28T16:06:37.41+00:00

    Here are the screenshots you requested:

    Windows version information (winver)

    Disk Management showing all partitions

    The update keeps failing with the error: “We couldn’t update the system reserved partition.”

    Please let me know the safest way to fix this without losing files or changing partitions incorrectly, since this is a new laptop.0d727b1a-e0df-450e-b2ff-17b918249d07

    a9268261-fb53-4117-87dd-3c925a3c98f3

    Was this answer helpful?

    1 person found this answer helpful.
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