What is a .part file?
Partial Download File · Data · Various (browsers, download managers) · n/a
A .part file is an incomplete download. Browsers like Firefox and download managers add the .part suffix to a file while it is still downloading, then rename it once the transfer finishes.
What is a .part file used for?
A .part is not a real format; it is whatever file was being fetched, only not finished yet. Its first bytes are the start of the real file (a PDF, a video, a ZIP), and the rest is missing.
If a download stalls, the .part may resume or may be abandoned. A leftover .part usually means the download failed; deleting it and downloading again is the normal fix.
How to open a .part file
The .part format opens in the following apps, grouped by operating system. If one app does not work, try another from the same list. For a step-by-step walkthrough, see how to open a .part file.
Windows
- Resume the download
- the download manager that made it
macOS
- Resume the download
Linux
- Resume the download
.part file signature (magic bytes)
Programs recognise a .part file by the bytes at the start of the file, not by its name. These are the signatures for PART.
| Hex signature | Offset | Note |
|---|---|---|
| (no fixed signature) | 0 | no format of its own; holds the partial bytes of the real file |
See the full magic-numbers reference for every format.
Frequently asked questions
What is a .part file?
A .part file is an incomplete download. Browsers like Firefox and download managers add the .part suffix to a file while it is still downloading, then rename it once the transfer finishes.
How do I open a .part file?
Normally you do not. Let the download finish, which renames it to the real file. A leftover .part is an unfinished download.
Can I recover a .part file?
Sometimes. If it is nearly complete, renaming it to the real extension may partly work, but the missing end usually makes it unusable. Re-downloading is more reliable.
Is it safe to delete a .part file?
Yes, if the download is not in progress. A stray .part is a failed or abandoned download and can be removed; just restart the download if you still need the file.
Related formats
Sources
Details on this page were checked against authoritative references: