Open C:\Windows\WinSxS in File Explorer and it can look enormous. The short answer: do not delete files from it by hand. Windows has supported commands that clean the component store safely.
WinSxS is the Windows component store. It holds the files Windows needs to install, update, repair and roll back system components. Many entries in it are hard links to the same files that live elsewhere in Windows.
Because of those hard links, the size File Explorer shows can count the same data more than once. The real extra disk space used is usually smaller than the number in the folder properties.
Removing files or folders from WinSxS manually, or taking ownership of the folder to do it, can break Windows Update, repair tools and optional features. If you have already done it, run sfc /scannow and DISM /Online /Cleanup-Image /RestoreHealth from an administrator Command Prompt.
Open Command Prompt as administrator and run: DISM /Online /Cleanup-Image /AnalyzeComponentStore
The report says whether a cleanup is recommended and how much could be reclaimed. If it says no cleanup is recommended, you can stop here.
If a cleanup is recommended, run: DISM /Online /Cleanup-Image /StartComponentCleanup
This removes superseded versions of components. It is the same job Windows does automatically through a scheduled task, just started on demand.
The /ResetBase option removes all superseded versions without keeping them, which can save more space but means you can no longer uninstall the updates that are already installed. It is optional and is not needed for normal cleaning, so skip it unless you understand the trade-off.
Disk Cleanup (cleanmgr) → Clean up system files → Windows Update Cleanup does a similar job without a command line. Read our Windows Update Cleanup guide before you use it.
Rain Cleaner (Windows 10/11, 64-bit) is built around inspection before deletion and does not delete files from WinSxS by hand. The Free version has no ads; Pro has a free 14-day trial (no card).
Last updated: 2026-10-01
No. It is the Windows component store. Use DISM or Disk Cleanup to clean it safely.
It stores component versions for updates and repair. File Explorer also counts hard-linked files more than once, so the shown size is overstated.
It works, but you will no longer be able to uninstall the updates that are already installed. It is optional.
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