Windows Update Fails: The Complete Fix

Published 2026 · 4 min read

Failed Windows updates usually come down to disk space, a corrupted update cache, or a stuck service.

1. Run the built-in troubleshooter

Settings → System → Troubleshoot → Windows Update finds and fixes most common problems automatically. Run it first.

2. Free up disk space

Updates need room to download and install. Free up 15-20% of your drive with Disk Cleanup → Clean up system files.

3. Clear the update cache

In an admin Command Prompt, stop the Windows Update service (net stop wuauserv), delete C:\Windows\SoftwareDistribution\Download, restart the service, then check for updates again.

4. When Windows undoes the update

That means install failed — often from space or a driver conflict. Disconnect extra USB devices and retry. If it keeps failing, search the specific error code online for the known fix.

Interactive version

Use the update fixer — tell it what happens and get the exact steps.

Most update failures are three things

Windows Update usually fails because there is not enough disk space, the update cache is corrupted, or a service is stuck. All three have simple fixes that clear the large majority of failed-update loops.

Free space and run the troubleshooter

Updates need several gigabytes. Free disk space, then run Settings > System > Troubleshoot > Other troubleshooters > Windows Update. The troubleshooter repairs the service and cache automatically in most cases.

Reset the update cache manually

If it still fails, stop the Windows Update service (services.msc), delete the contents of C:\Windows\SoftwareDistribution\Download, restart the service, and try the update again. This clears corrupted partial downloads.

DISM and SFC when corruption is deep

Open an elevated Command Prompt and run DISM /Online /Cleanup-Image /RestoreHealth, then sfc /scannow, and reboot. These repair system files that make updates fail repeatedly.