If you’ve ever run the Windows Disk Cleanup utility, you probably discovered that your temporary files occupy a significant amount of space. You might select the Temporary Files check box in order to allow the Disk Cleanup utility to delete the files in the Temp folder, but the Disk Cleanup utility will not remove all of the files.

The reason for this oddity is that the configuration for the Disk Cleanup utility does not allow deletion of files accessed in the last seven days.

By altering the LastAccess value in the registry, you can configure the Disk Cleanup utility to delete all the files in the Temp folder regardless of the last accessed date. Here’s how: Open regedit; Go to HKEY_LOCAL_MACHINE\ SOFTWARE\ Microsoft\ Windows\ CurrentVersion\ Explorer\ VolumeCaches\ Temporary Files. Locate and double-click the LastAccess value. When you see the Edit DWORD Value dialog box, change the Value Data setting from 7 to 0 and click OK. Restart Windows.

This works on XP and Vista too.

In Windows Vista, there is also an Enhanced Version of the Disk Cleanup Tool ! It basically just has more options for you to choose so you can delete some addl files.

To access it just click Start > Run

cleanmgr /sageset:1

and hit enter.

Do note that this does not actually clean anything. You are just setting the options that would be used if you were to run the cleanmgr /sagerun:1 command later.

In short, after you click OK, the settings (selection) will be stored in the Registry for future use. When you schedule it to run through the Task Scheduler, it will take these settings for Disk Cleanup.

The number after the colon can be anything up to 255. This number basically lets you make shortcuts to different stored configurations or schedule automatic cleanup in the Task Scheduler.

A registry tweak from here replaces the Delete command from the Recycle Bin with a Clear Temp command. This prevents users from accidentally deleting the Recycle Bin Icon from the Desktop. It also adds a Disk Cleanup command which performs an Extended Disk Cleanup on all disks. The Clear Temp command clears both Temp directories: %UserProfile%\ AppData\ Local\ Temp & %SystemRoot%\ Temp.
Always best to create a SystemRestore Point before applying such tweaks.

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