What happens to the Windows Update files once the update is applied?

After watching almost 2 gigabytes of updates being applied to a new system, I'm curious..

Does Windows Update remove or delete the updates it has successfully downloaded and installed, or is that something I need to do manually in order to reclaim some disk space?

Answer

Interesting question.

In first place, update packages are stored in c:\windows\softwaredistribution.

Windows updates are installed using Windows Installer. Some are uninstallable and some are not.

For the first case, windows installer keep tracks of changes so they can be undone. This include files backup.

For the second case, no backup will be made.

When running out of disk space, just let Windows Cleanup Utility decide which updates to delete.

Is it ok and how do I remove Windows Update installation files?

Safe to delete "C:\WINDOWS\SoftwareDistribution\Download"