Fixes / Windows · Checked

Windows "We couldn't complete the updates. Undoing changes": fix

Short answer

Windows tried to install an update. Something failed during the restart, so Windows is putting your PC back the way it was before the update. Your files are safe. Let it finish, which can take 30 minutes or more. Once you are back at the desktop, clear the update cache (the SoftwareDistribution folder), make sure you have at least 20 GB free on C:, and run the update again.

What this message means

Windows installs most of an update during the restart, in the part you see as "Working on updates". If any part of that fails, whether that's a corrupted download, a driver or security program blocking it, or too little disk space, Windows reverses every change so the PC can still start. This message is that rollback. It is a safety feature, not a crash, and your documents and apps are not deleted. The update will usually download again and fail the same way until you fix what caused it. Do not power off during the rollback. Cutting the power while system files are being restored is what can actually stop Windows from starting.

Common causes

CauseHow to tell
Corrupted or incomplete update files in the Windows Update cacheThe same KB number fails again every time. In Update history it shows as "Failed to install", often with an error code such as 0x800f0922 or 0x8007000d.
Not enough free space on the system drive (C:) or on the small System Reserved / EFI partitionThis Pc shows C: with only a few GB free (a red bar), or the failure code is 0x800f0922 or 0x80070070. It happens most often on 64 GB or 128 GB laptops and tablets.
Third-party antivirus, VPN software or an outdated driver blocking files during installationThe failures began after you installed a security suite, VPN or hardware utility. Error 0xC1900101 points to a driver problem. The update usually installs once that software is uninstalled.
Damaged Windows system files or component storesfc /scannow reports "found corrupt files", or DISM reports that the component store is repairable. Other Windows features may also misbehave.
A faulty update released by MicrosoftYour PC is otherwise healthy, every fix above does nothing, and forums or Microsoft's Windows release health page mention the same KB failing for many other users.

How to fix it

1. Let the rollback finish, then check which update failed

Windows 10 and Windows 11

  1. Leave the PC on and plugged in until you reach the sign-in screen. The rollback can take 30 minutes or more, and on slow hard drives it can take a couple of hours.
  2. Sign in. On Windows 11, go to Start > Settings > Windows Update > Update history. On Windows 10, go to Start > Settings > Update & Security > Windows Update > View update history.
  3. Write down the KB number and the error code of the entry marked "Failed to install". You will use them for the later fixes and for searching.
  4. Restart once more and run Check for updates. A one-time glitch sometimes installs fine on the second try.

2. Free up space on drive C:

Windows 10 and Windows 11

  1. Open File Explorer, select This PC and check how much space is free on C:. Aim for at least 20 GB free before a feature update.
  2. Press the Windows key, type Disk Cleanup and open it. Select drive C: and click Clean up system files.
  3. Tick Temporary files, Windows Update Cleanup and Recycle Bin, then click OK.
  4. Move large personal files (videos, old downloads) to an external drive or cloud storage if you still need more space.
  5. Restart and run Check for updates again.

3. Run the Windows Update troubleshooter

Windows 11: Settings > System > Troubleshoot. Windows 10: Settings > Update & Security > Troubleshoot

  1. Windows 11: go to Start > Settings > System > Troubleshoot > Other troubleshooters. Next to Windows Update, select Run.
  2. Windows 10: go to Start > Settings > Update & Security > Troubleshoot > Additional troubleshooters. Select Windows Update > Run the troubleshooter.
  3. Apply any fixes it offers, restart and try the update again.

4. Reset the Windows Update cache

Windows 10 and Windows 11. If it still fails, do this in Safe Mode

  1. Press the Windows key, type cmd, right-click Command Prompt and choose Run as administrator.
  2. Run these one at a time: net stop bits, then net stop wuauserv.
  3. Run: ren %systemroot%\SoftwareDistribution SoftwareDistribution.bak
  4. Run: ren %systemroot%\System32\catroot2 catroot2.bak
  5. Run: net start bits, then net start wuauserv.
  6. Restart and run Check for updates. Windows downloads a fresh copy of the update.
  7. If a service will not stop or the rename fails, boot into Safe Mode (Settings > Recovery > Advanced startup > Restart now > Troubleshoot > Advanced options > Startup Settings > Restart > 4) and repeat these steps. Many users report that this is what finally works.

5. Repair system files with DISM and SFC, and temporarily remove third-party antivirus

Windows 10 and Windows 11

  1. Open Command Prompt as administrator.
  2. Run: DISM.exe /Online /Cleanup-image /Restorehealth (this needs internet and can sit at 20% or 60% for several minutes).
  3. Run: sfc /scannow and wait for it to reach 100%.
  4. Run: chkdsk /f C: and type Y to schedule the check for the next restart.
  5. Uninstall any third-party antivirus through Settings > Apps (Microsoft Defender turns itself back on). Also disconnect USB drives, docks and other peripherals you don't need.
  6. Restart, install the update, then reinstall your antivirus.

6. Reinstall Windows in place (keeps files and apps) or pause the update

Reinstall via Windows Update: Windows 11 22H2 or later. Windows 10: use the Media Creation Tool instead

  1. Windows 11: go to Start > Settings > System > Recovery. Under Fix problems using Windows Update, select Reinstall now. This reinstalls your current version with the latest updates and keeps your files, apps and settings.
  2. Windows 10: download the Media Creation Tool from Microsoft's Windows 10 download page, choose Upgrade this PC now, and pick Keep personal files and apps.
  3. If you would rather wait for Microsoft to fix a faulty update, pause updates. On Windows 11, go to Settings > Windows Update > Pause updates. On Windows 10, go to Settings > Update & Security > Windows Update > Pause updates for 7 days. The next monthly update often replaces the failing one.

7. If the PC loops on this message and never reaches the desktop

Windows 10 and Windows 11 (BitLocker devices will ask for the recovery key)

  1. If the rollback message comes back after every restart, turn the PC off with the power button when the Windows logo appears. Do this twice. On the third start, Windows opens Automatic Repair.
  2. Select Advanced options > Troubleshoot > Advanced options.
  3. Choose Uninstall Updates > Uninstall latest quality update (or latest feature update if you were upgrading Windows versions).
  4. If that fails, go back and choose System Restore, then pick a restore point dated before the update.
  5. Once Windows starts, pause updates and work through the fixes above before trying again.

Next time, skip the search

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Still not fixed?

Search the KB number and error code from Update history together (for example "KB5043145 0x800f0922"), and check Microsoft's Windows release health page to see if the update is a known issue. For deeper detail, open Command Prompt as administrator and look at C:\Windows\Logs\CBS\CBS.log, or run Get-WindowsUpdateLog in PowerShell to create a readable log on your desktop. At work or school, contact your IT department, because updates are often controlled by policy. At home, use the Get Help app to reach Microsoft Support. If nothing else works, use Settings > System > Recovery > Reset this PC with Keep my files as a last resort.

Questions people ask

How long does "Undoing changes" take?

It usually takes 15 to 30 minutes, but on older PCs with hard drives or with large feature updates it can run for 1 to 2 hours. If the screen hasn't changed and the drive light hasn't flashed for more than 3 hours, a forced shutdown is reasonable.

Can I turn off my computer during "Undoing changes"?

Avoid it. Powering off while Windows is restoring system files can leave it unable to boot. If you have to, Windows will usually open Automatic Repair, where you can use Uninstall Updates or System Restore.

Will I lose my files?

No. The rollback only reverses the system changes the update made. Your documents, photos and installed apps stay where they were.

Why does the same update keep failing?

Windows downloads the same update again and hits the same problem, which is usually a corrupted cache, low disk space or a program that blocks it. Reset the update cache and free up space. If it still fails, pause updates until Microsoft releases the next cumulative update.

My PC is stuck in a loop of "Undoing changes". What now?

Interrupt startup twice to open Automatic Repair, then go to Troubleshoot > Advanced options > Uninstall Updates and remove the latest quality update. You can also use System Restore to go back to a point before the update.

Sources

Related errors