In Storage settings you may see Delivery Optimization Files using a surprising amount of space. They are a cache that Windows rebuilds when it needs it, so clearing them is normally harmless.
Delivery Optimization is the Windows service that downloads updates and Microsoft Store apps. It keeps a local cache of the pieces it downloaded, and it can share those pieces with other PCs if you allow it.
Yes. They are cached download data, not your files or your settings. If Windows needs a piece again it downloads it again. Avoid clearing them while an update is downloading or installing.
The cache keeps recent update data for a while so it can be reused, and large cumulative updates and big Store apps add up. Windows manages the cache itself and trims it over time, which is why the size changes.
Open Settings → System → Storage → Temporary files. Wait for the scan, tick Delivery Optimization Files and look at the size shown. Remove only the categories you have read.
Search for Disk Cleanup (or run cleanmgr), choose the Windows drive and, if Delivery Optimization Files is listed, tick it. Click Clean up system files for more categories, then confirm.
You do not need to turn it off to clean the cache. Under Settings → Windows Update → Advanced options → Delivery Optimization you can choose whether Windows may download updates from other PCs. Turning that off does not stop updates from installing.
Nothing breaks. The next update or app download may take slightly longer because Windows has to fetch the data again, and the cache starts growing again.
Rain Cleaner (Windows 10/11, 64-bit) shows what it found, with an explanation for each item, before it removes anything. The Free version has no ads; Pro has a free 14-day trial (no card). The Windows tools above are enough on their own.
Last updated: 2026-10-01
Yes. They are a download cache that Windows rebuilds when needed.
No. Updates still download and install; they may just need to fetch data again.
Windows caches update and app downloads again as it needs them.
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