Clearing delivery optimization files?

When you run disk cleaup (cleanmgr) there is a checkbox option to clean delivery optimization files, see attached screenshot below.

I have 2 computers (Win 10, and Win 11) and using delivery optimization on both, both are on same LAN, if I run disk cleanup and clean those DO files, will that make windows having to re-download windows updates?
Is it safe to delete those files, that is, will DO be affected by performance and download wise if I clean them?

zebal said:

If I run disk cleanup and clean those DO files, will that make windows having to re-download windows updates?

Click to expand...

No

zebal said:

Is it safe to delete those files, that is, will DO be affected by performance and download wise if I clean them?

Click to expand...

Seeing as you are deleting - possibly - 4-5+Gb after a major update, then you may see a slight improvement in performance.

However, it always good practice to take an image BEFORE & AFTER every update.

Therefore updates downloaded and used by delivery optimization are stored somewhere and this option does not delete those downloaded files?
I assume that'd be SxS folder and those optimization files are not those from SxS?

zebal said:

Therefore updates downloaded and used by delivery optimization are stored somewhere and this option does not delete those downloaded files?

Click to expand...

The downloaded updates are stored in "C:\Windows\SoftwareDistribution".

Delivery Optimization is a local caching service designed for a setup like yours. Two or more PC's on the local network can share updates already downloaded on one PC -- saving you extra network traffic to the outside world. This is great if you're on a slow connection, or have metered cellular access.

PC's will cross-check if another PC already has cached the same updates, Store apps, or other Windows install files. You can set policies to define how files are to be distributed and the fallback methods. DO is completely optional, and you can disable it.

Delivery Optimization - Windows Deployment

Thank you guys, I would also like to know what are those delivery optimization files which can be cleared in diskcleanup?
anyone knows what's their purpose?

Default max cache age is 3 days. If you have Defender enabled, it might be daily signature updates taking up the 4 MB.
For comparison, check Disk Cleanup after Patch Tuesday if the size grows.