What is a .tmp file?
Temporary File · Data · Various · n/a
A TMP file is scratch data a program writes while it works, such as an autosave, a download in progress or install staging. Most are meant to be deleted automatically and are safe to remove once the program that made them is closed.
What is a .tmp file used for?
Programs create .tmp files as temporary workspace: buffering large edits, staging an installer, holding an autosave, or caching data mid-task. The name and contents are private to whatever produced them.
Normally the program cleans up its own .tmp files when it finishes. They get left behind when an app crashes or is force-quit, which is why old .tmp files pile up in temp folders.
You can usually delete stray .tmp files safely once the program is closed. Occasionally a .tmp is a recoverable autosave, so if you lost work, it can be worth renaming a recent one back to the original extension and opening it in the app.
There is no universal viewer. A text editor can reveal whether a given .tmp is readable text, but a .tmp is only meaningful to the program that wrote it.
How to open a .tmp file
The .tmp format opens in the following apps, grouped by operating system. If one app does not work, try another from the same list.
Windows
- The program that created it
- Disk Cleanup (to remove)
- text editor (to inspect a recoverable one)
macOS
- The originating program
- text editor (to inspect)
Linux
- The originating program
- text or hex editor
Web
- Not applicable
How to convert a .tmp file
You can convert a .tmp file to Rename to the original extension if you know what it is using a conversion tool or the export menu of an app that opens it.
.tmp file signature (magic bytes)
Programs recognise a .tmp file by the bytes at the start of the file, not by its name. These are the signatures for TMP.
| Hex signature | Offset | Note |
|---|---|---|
| (no fixed signature) | 0 | no fixed signature; a .tmp mirrors whatever data the program was holding |
See the full magic-numbers reference for every format.
Frequently asked questions
What is a .tmp file?
A TMP file is scratch data a program writes while it works, such as an autosave, a download in progress or install staging. Most are meant to be deleted automatically and are safe to remove once the program that made them is closed.
Can I delete TMP files?
Generally yes. Close the program that might be using them, then remove stray .tmp files with Disk Cleanup on Windows or by emptying the temp folder. Files in active use are locked and cannot be deleted until the program releases them.
How do I open a TMP file?
Most .tmp files are not meant to be opened. If you are trying to recover lost work, rename a recent one to the original extension (for example .docx) and open it in the matching program. Otherwise a text editor can show whether it holds readable content.
Related formats
Sources
Details on this page were checked against authoritative references: