WinSxS is the Windows component store, located at C:\Windows\WinSxS. It stores every version of the system files Windows uses to install updates, enable features, and roll changes back if something breaks. You can safely reclaim space from it, but only with the supported command, not by deleting files:

Dism.exe /Online /Cleanup-Image /StartComponentCleanup

Run that from an elevated Command Prompt (Run as administrator) and Windows removes superseded component versions on its own.

TL;DR

  • WinSxS holds versioned system components so Windows can install/uninstall updates and features reliably.
  • Its size is overstated: File Explorer counts hard links multiple times, so the real footprint is smaller than it appears.
  • Shrink it with Dism.exe /Online /Cleanup-Image /StartComponentCleanup, optionally adding /ResetBase.
  • Never delete, move, or rename anything inside WinSxS by hand. You can break Windows Update or the OS itself.
  • Expect to recover a few hundred MB to a few GB, not tens of GB.

Why does WinSxS look so large?

Open C:\Windows\WinSxS in File Explorer, check properties, and you may see 8-15 GB or more. That number is misleading. Many files in WinSxS are hard links to files that also live in folders like System32. The same bytes on disk are counted once by Windows and again by Explorer, inflating the total.

To see the real, deduplicated size, use DISM:

Dism.exe /Online /Cleanup-Image /AnalyzeComponentStore

This reports the actual store size, the shared-with-Windows portion, the backups-and-disabled-features portion, and whether cleanup is recommended.

How do I safely shrink WinSxS?

Use the built-in DISM cleanup, which removes only superseded component versions that Windows no longer needs:

Dism.exe /Online /Cleanup-Image /StartComponentCleanup

To also remove all superseded versions of every component (so past updates can no longer be uninstalled), add /ResetBase:

Dism.exe /Online /Cleanup-Image /StartComponentCleanup /ResetBase

The Disk Cleanup tool offers the same thing under a friendlier name: run cleanmgr, click Clean up system files, and tick Windows Update Cleanup. Both routes call the same underlying servicing engine.

What Windows does natively, and where it stops

Windows already maintains WinSxS automatically. A scheduled task named StartComponentCleanup runs in the background and removes components that have been superseded for at least 30 days. So in most cases you do not need to touch this at all.

Where it stops: the automatic task is conservative and time-delayed, it never runs /ResetBase, and it won't free space on demand. If you need room right now, or want to flush the full backup set, you run DISM manually. Beyond that, Windows offers no supported way to make the component store smaller, by design.

What this cannot do, and what to leave alone

Cleanup will not shrink WinSxS to a token size. The store must keep the live components Windows is currently running, so a multi-GB folder is normal and healthy. Do not expect it to disappear.

Never delete, move, rename, or take ownership of files inside C:\Windows\WinSxS. Those hard links are shared with the rest of the OS, and removing them can corrupt Windows Update or prevent the system from booting. There is no safe manual edit here. The only supported tools are DISM and Disk Cleanup.

If you ran /ResetBase, be aware of one trade-off: you can no longer uninstall any update that was installed before the reset. That is usually fine, but skip it right after a major feature update you might want to roll back.

Looking for bigger wins elsewhere? See how to find the largest files on Windows 11 without third-party apps, and if you're considering NTFS compression, read is it safe to compress the C: drive to save space first.

FAQ

Can I delete the WinSxS folder to free space?

No. WinSxS contains live, hard-linked system components, and deleting it can break Windows Update or stop the OS from booting. Use Dism.exe /Online /Cleanup-Image /StartComponentCleanup instead, which removes only the versions Windows no longer needs.

How much space will StartComponentCleanup actually free?

Usually a few hundred MB to a few GB, depending on how many updates have accumulated since the last cleanup. Run AnalyzeComponentStore first to see the "backups and disabled features" figure, which is roughly what's reclaimable.

Does /ResetBase have any downside?

Yes. After /ResetBase, you can no longer uninstall any update installed before you ran it. It frees the most space, but skip it immediately after a feature update you might want to roll back.

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