What Is a TMP File?
Your disk is full of .tmp files and you want to know if you can delete them. They are temporary scratch files. Here is what makes them and how to clear them safely.
What a TMP file is
A .tmp file is a temporary working file that a program writes while it is busy — Microsoft Office while you edit a document, an installer while it unpacks, or a browser while it caches. The program is supposed to delete the file when it is done, but crashes, forced shutdowns, and interrupted installs leave orphaned .tmp files behind.
Where they come from
Office apps create hidden temp copies (often starting with ~) so they can recover your work after a crash. Installers extract into .tmp files in your Windows Temp folder. These are normal — a healthy system always has some.
Is it safe to delete?
Usually yes, once the program that made it is closed. A .tmp left over from a closed app or a finished install is just wasted space. The one rule: never delete a .tmp belonging to a program that is currently running — it may be actively using it, and removing it can crash the app or lose unsaved work.
How to clean them up safely
The safe way is not to hunt them by hand. On Windows, use Disk Cleanup or Settings → System → Storage → Temporary files, or press Win+R, type %temp%, and delete what the folder lets you (files in use are skipped automatically). On a Mac, temp files live in system caches that macOS clears on its own. Close your applications first so no live temp files are in use.
Can you open a TMP file?
There is rarely a reason to. A .tmp may contain anything — text, a partial document, compressed installer data. A text editor can show fragments, and occasionally renaming a recovered Office .tmp to .docx or .xlsx rescues lost work, but most of the time a leftover temp file is disposable.
FAQ
Is it safe to delete TMP files?
Usually yes, as long as the program that created them is closed. Never delete a .tmp belonging to an app that is currently running — it may be in use and you could lose unsaved work.
How do I clean up TMP files on Windows?
Use Disk Cleanup or Settings → System → Storage → Temporary files, or open the Run box (Win+R), type %temp%, and delete what the folder allows. Files still in use are skipped automatically.
Can a TMP file recover a lost document?
Sometimes. Office keeps hidden temp copies for crash recovery; renaming a matching ~*.tmp to .docx or .xlsx occasionally restores unsaved work. Check the app's AutoRecover first.
Why do TMP files keep coming back?
Because programs constantly create them while working. That is normal — a system always has some. They only pile up when apps crash or are force-closed before cleaning up.