Open C drive, open Windows, and there it sits: WinSxS, apparently eating ten or fifteen gigabytes. The internet's worst advice says delete it. That advice breaks Windows Update, breaks repairs, and can leave a PC that nothing can fix. The real story is more interesting — the size is partly an illusion, and Microsoft provides a cleanup that actually works.
WinSxS is the component store: every version of every system component Windows needs to service itself, install updates and repair files. It looks enormous in Explorer partly because many of its files are hard links — the same data also counted inside the Windows folder — so the displayed size double-counts. Deleting files by hand corrupts the store's bookkeeping, and a corrupted store means failed updates with no clean way back. The supported route is slower, duller and completely safe: analyse with DISM, then let DISM remove what is genuinely superseded.
👆 Example analysis output. The gap between the reported size and the actual size is the hard-link illusion — shared files counted twice.
Explorer adds up every file it can see. In WinSxS, many entries are hard links to data that physically exists once and is shared with the live Windows folder.
The honest question is never how big the folder looks. It is how much DISM says is reclaimable.
DISM /Online /Cleanup-Image /AnalyzeComponentStoreIf the verdict is No and reclaimable packages are zero, your store is already lean and no cleanup on earth will shrink it further. Believe the report.
DISM /Online /Cleanup-Image /StartComponentCleanupThis removes component versions that have been superseded past their grace period — the genuinely dead weight. Gains vary honestly: a few hundred megabytes on a fresh install, several gigabytes on a PC with years of updates.
Adding /ResetBase goes further: DISM /Online /Cleanup-Image /StartComponentCleanup /ResetBase removes all superseded versions, squeezing the store to its minimum.
The price is permanent and must be understood before running it: after ResetBase, installed updates can no longer be uninstalled. On a stable, fully updated PC that trade is often fine. On a machine you are still troubleshooting, it burns your rollback bridge. Choose deliberately, not by default.
For the rest of the full-drive rescue order, watch the reserved storage video and work through this series in sequence.
▶️ Watch Full VideoIt varies with update history — from a few hundred megabytes to several gigabytes. The analysis report's reclaimable packages count is the best prediction before you run it.
No. On slow drives the cleanup legitimately runs for a long time at high CPU and disk use. Interrupting servicing mid-flight is how component stores get damaged — let it finish.
It is a supported switch and safe on a healthy, stable system. Its cost is flexibility, not stability: you give up the ability to uninstall updates that were installed before you ran it.