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Trying to figure out where all the room on my new laptop went I found over 90GB eaten up by my c:\Windows\Temp directory.

None of these files I recognize and many seem to have not changed in months. Does anyone know what these oddly named files (prefixed with TMP) are and if they are safe to delete manually?

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I used to know what Windows puts there, but I can't remember it right now. I do remember that it's generally safe to delete the contents of this folder immediately after a reboot.

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Installation files are usually extracted into the temp folder if they are packed into a single file. Internet browsers will normally save files to this folder if you select "Open" before downloading them. Some other programs may use it for caching data that is only needed temporarily.

Windows Explorer also uses this folder to store the contents of .zip files if you open them directly, but they should be deleted as soon as you close the archive.

It normally is safe to delete the contents of this folder. (Windows will ask to do it automatically when there is not much space left on the disk.)

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I have very little space left and I have run the disk cleanup utility. It does not touch these files. Either way, you have to agree that windows should never have 90GB of these files. – George Mauer Aug 7 '10 at 23:56
They seem to have moved it since Vista. My TEMP still points to "C:\Windows\TEMP", but they probably had to change it because of UAC. Anyway, whichever program wrote these files, it seems to have had admin rights. – Tamschi Aug 12 '10 at 20:47

You can also use the "Disk Cleanup" tool included with Windows to clear out your temp folder.

I find this works better than deleting the files manually, as it avoids the dreaded "could not delete file X: the file is in use" message you often get when deleting the Windows temp folder.

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Unfortunately this is post-disk cleanup – George Mauer Aug 7 '10 at 23:57
It's odd that the files are in \Windows\Temp - I would have thought by now you'd find them in the per-user temp folder (:\Users\UserName\AppData\Local\Temp) or in the all-users temp folder (:\ProgramData\Temp). I thought the \Windows\Temp folder was depreciated. I wonder what program is putting those files there... – Keithius Aug 8 '10 at 14:02

Windows/Temp is (appropriately) Windows' Temporary files folder. It holds stuff that programs think won't be needed after a while. It's generally safe to empty this folder out, though it's a better idea to use CCleaner to clean this folder because it removes only old files, leaving the new ones that may still be in use behind.

From your screenshot, your computer could definitely use a reinstall if you have the time.

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