You can select this option to free up some space and Windows 10's built-in antivirus will continue running normally. Microsoft doesn't explain what these files are anywhere, but it's likely they're just temporary files.

Windows Defender: This option deletes 'non critical files used by Windows Defender', according to the Disk Cleanup tool.

However, if you don't plan on ever uninstalling any Windows updates, this is a waste of space. This is safe to delete as long as your computer is working properly and you don't plan on uninstalling any updates. This allows you to uninstall the updates later.

Windows Update Cleanup: When you install updates from Windows Update, Windows keeps older versions of the system files around.

Some options may only appear if you have certain types of system files on your hard drive.

Older versions of Windows may have slightly fewer options.

Note that we used Disk Cleanup on a PC running Windows 10 with the Anniversary Update installed. So what do all the other options do? We went through Disk Cleanup and made a list. Related: How to Reduce the Size of Your WinSXS Folder on Windows 7, 8, 10, and 11

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