Hi, @Ximing Feng
1.Why/How are those folders generated?
The Wsusscan.cab file come with every new security release, the files contains metadata from the following classifications: security updates, update rollups, and service packs. These files usually should be automatically deleted after an update is completed, but some installation error during the update might prevent that.
2.How can I remove the folders
You could delete these files by taking the ownership of that folder.
Please note that it’s safer to let the Disk Cleanup tool do these cleanings for you, this avoids accidentally deleting files that you need, and don't forget to make a system backup.
3.Is there anything that I can do to prevent this kind of folders to be created?
Based on my research, I’m afraid these isn’t a direct way to prevent this, You could perform Disk Cleanup to remove these files after a successful update.
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