Are .tmp Files Safe to Delete?
Short answer: yes, .tmp files are safe to delete — as long as the program that made them is closed. They are scratch files apps meant to remove themselves but often don't.
The verdict
Safe to delete when the owning app is closed. A .tmp file is temporary working data — a program writes it while it runs (an autosave buffer, an unpacked chunk, a print spool) and is supposed to delete it on exit. Crashes, forced shutdowns, and lazy cleanup leave them behind, so they pile up in temp folders and waste space.
The one rule
Do not delete a .tmp that a running program is still using — you could lose unsaved work or crash the app. The safe move is to close your programs first (especially Office apps, editors, and installers), then clear the temp files. Windows will not let you delete a .tmp that is actively locked, which is your safety net.
How to clear them safely
- Use the built-in tool. Press Win+R, type
%temp%, press Enter, select all, and delete. Skip anything Windows says is in use. - Or use Disk Cleanup / Storage Sense. Settings → System → Storage → Temporary files handles this without touching anything active.
- Empty the Recycle Bin afterwards to actually reclaim the space.
Are they ever a virus?
The .tmp extension is not malware, but malware droppers sometimes stage a payload as a .tmp in a temp folder before running it. A .tmp cannot run on its own, so simply deleting it is safe. If temp files reappear constantly with odd names, run a full malware scan.
Will deleting them cause problems?
No — for closed apps the data was disposable. The only risk is deleting the scratch file of an app you have open, which is why you close programs first.
FAQ
Is it safe to delete .tmp files?
Yes, as long as the program that created them is closed. Windows blocks deletion of any .tmp still in active use, so you cannot accidentally break a running app that way.
How do I delete temp files in Windows?
Press Win+R, type %temp%, press Enter, select all and delete — or use Settings → System → Storage → Temporary files. Then empty the Recycle Bin to reclaim space.
Can a .tmp file be a virus?
The extension is not malware, but droppers sometimes stage a payload as a .tmp. A .tmp cannot run by itself, so deleting it is safe; run a full scan if temp files keep reappearing with strange names.