Delivery Optimization files
Also known as: Delivery Optimization cache, Windows Update peer cache, DO files
Delivery Optimization files are cached pieces of Windows updates and Store apps that your PC keeps to speed up installs and share with other devices on your network. The cache is safe to clear and Windows refills it only as needed.
- Caches update and Store-app downloads
- Cleared via Disk Cleanup or Storage settings
- Safe to clear; refilled only when needed
What the cache is for
Delivery Optimization lets Windows download updates and Microsoft Store apps in pieces — from Microsoft and, optionally, from other PCs on your local network or the internet. The downloaded chunks are cached so installs are faster and bandwidth is shared, which can leave a few gigabytes sitting on disk.
How to clear it
Run Disk Cleanup and tick Delivery Optimization Files, or use Settings > System > Storage > Temporary files and select that category. To control the sharing behavior itself, go to Settings > Windows Update > Advanced options > Delivery Optimization. Clearing the cache only removes downloadable update pieces, nothing personal.