Delivery Optimization is the background service Windows uses to share downloaded update payloads across your network (or, by default, with other PCs on the internet). Its cache lives in C:\Windows\ServiceProfiles\NetworkService\AppData\Local\Microsoft\Windows\DeliveryOptimization and can reach 10 GB.

Short answer: open Settings > System > Storage > Temporary files, tick Delivery Optimization Files, and click Remove files. No reboot needed.

What Delivery Optimization does

After Windows downloads an update, it keeps the update payload cached so:

  • other PCs on your local network can grab it from you instead of re-downloading from Microsoft
  • (optionally) other PCs anywhere on the internet can grab it too
  • if the current update fails and needs to resume, the payload is already local

The cache is useful on corporate networks with dozens of PCs; at home, it rarely pays off and is safe to wipe.

Clearing the cache

Quick way (Storage Sense)

  1. open Settings > System > Storage
  2. click Temporary files
  3. wait for the scan
  4. tick Delivery Optimization Files
  5. click Remove files

Advanced way (Disk Cleanup)

  1. press Start, type cleanmgr, press Enter
  2. choose drive C:
  3. click Clean up system files and re-select C:
  4. tick Delivery Optimization Files
  5. click OK

Limiting how much it ever caches

  1. Settings > Windows Update > Advanced options > Delivery Optimization
  2. toggle Allow downloads from other PCs Off — or scope to Devices on my local network only
  3. (not exposed in UI) cap cache size via Group Policy or registry — at home, turning the service off is simpler than capping it

Turning Delivery Optimization off does not prevent Windows Update from downloading updates normally; it only prevents peer-to-peer sharing.

Better next routes

For the stuck-update cousin, continue with How to Clear the Windows Update Cache (SoftwareDistribution).

For the broader Windows cleanup, read How to Free Up Space on C Drive Windows 11 Natively.