Fix Windows Update Error 0x80070020 – File Locked

You're trying to run Windows Update, maybe installing the latest monthly patch or a driver update, and halfway through it throws 0x80070020. The update bar freezes, then fails. This happened to a client of mine last week on a Dell laptop running Windows 11 22H2 – they had a third-party antivirus scanning in the background. The error means a file that Windows Update needs is locked by another process. Could be your antivirus, a backup tool, or even a stuck Windows service.

What Actually Causes This Error

The error code 0x80070020 translates to ERROR_SHARING_VIOLATION – plain English: another program has the file open and won't let go. Windows Update downloads files to C:\Windows\SoftwareDistribution\Download. If something like Windows Defender real-time scanning, a third-party antivirus, or even an old update installer is using that file, the update fails. The trigger is almost always a background service or security tool that's too aggressive.

I've seen this most often after a system wakes from sleep or hibernate. The update service starts but some other service didn't release its lock properly. Also common after installing a new antivirus – it starts scanning everything mid-update.

Step-by-Step Fix

Boot into Safe Mode with Networking. This bypasses most third-party services. Hold Shift while clicking Restart, then Troubleshoot > Advanced Options > Startup Settings > Restart, then press 5 for Safe Mode with Networking.
Stop the Windows Update services. Open Command Prompt as Administrator (right-click Start, choose it). Run these commands one at a time:
```
net stop wuauserv
net stop cryptSvc
net stop bits
net stop msiserver
```
Delete the temporary update folders. These folders hold the locked files. Run:
```
ren C:\Windows\SoftwareDistribution SoftwareDistribution.old
ren C:\Windows\System32\catroot2 Catroot2.old
```
This renames them, so Windows creates fresh ones on restart.

Restart the services. Same Command Prompt:

net start wuauserv
net start cryptSvc
net start bits
net start msiserver

Reboot normally and run Windows Update again.

If that doesn't fix it, the culprit is likely a third-party antivirus. Disable real-time protection temporarily. For Windows Defender, you can turn off real-time scanning in Virus & Threat Protection settings. For McAfee, Norton, or Bitdefender, open the app and pause protection for 10 minutes. Then try the update again.

Still Failing? Check These

Corrupt system files. Run sfc /scannow in Command Prompt as Admin. If it finds issues, run DISM /Online /Cleanup-Image /RestoreHealth.
Disk space low? Windows Update needs room to download and install. Check your free space in Settings > System > Storage. Aim for at least 10GB free.
Check the Windows Update log. Look at C:\Windows\WindowsUpdate.log for exact file paths that are locked. Search for "0x80070020" in that file to see which file caused the issue.

I've seen this error resolved by simply rebooting twice – once to clear locks, once to retry. But if the steps above don't work, the problem is usually a persistent service or driver locking the file. Use Process Explorer (free from Microsoft) to search for the file name mentioned in the log, then kill that process. Had a client once where a stuck OneDrive sync process was locking the update files – killed it, update ran fine.