Is it safe to delete Windows Update files? (SoftwareDistribution explained)
Yes. Use Settings → System → Storage → Temporary files and tick Windows Update Cleanup and Delivery Optimization Files. If you want to clear the download folder by hand, stop the Windows Update service first and only empty SoftwareDistribution\Download.
Windows Update downloads every update to your PC before installing it, and keeps several kinds of leftovers afterwards. Together they can easily take 5–15 GB.
The three kinds of update leftovers
- Downloaded update files in
C:\Windows\SoftwareDistribution\Download. Once updates are installed, these are just copies. - Delivery Optimization files: updates your PC keeps so it can share them with other PCs. Safe to delete.
- Superseded components in
C:\Windows\WinSxS: older versions of system files replaced by updates. Never delete these by hand; use the tools below.
The easy, safe way
- Open Settings → System → Storage → Temporary files.
- Tick Windows Update Cleanup and Delivery Optimization Files.
- Click Remove files.
Clearing SoftwareDistribution\Download by hand
This is also the classic fix when Windows Update is stuck. Open Terminal (Admin) or Command Prompt as administrator and run:
net stop wuauserv
net stop bitsThen delete everything inside C:\Windows\SoftwareDistribution\Download (not the folder itself), and start the services again:
net start wuauserv
net start bitsDon't delete the whole SoftwareDistribution folder unless you're troubleshooting. It also holds your update history, which gets reset.
Shrinking WinSxS properly
If WinSxS is huge, ask Windows to clean up superseded components itself:
DISM /Online /Cleanup-Image /StartComponentCleanupIt can take a while, and you won't be able to uninstall updates that were already installed.