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.
What opens 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.
Windows
- Resume the download
- the download manager that made it
macOS
- Resume the download
Linux
- Resume the download
Open a .part file step by step
- Confirm the file really is a .part. Drop it into the WhatFileType identifier, which reads its signature in your browser without uploading anything.
- On Windows, open it with Resume the download or the download manager that made it.
- On Mac, use Resume the download.
- On Linux, try Resume the download.
- Still stuck? Search for a dedicated PART viewer rather than a generic one.
Why can't I open my .part file?
Almost always because no installed app understands PART. Install one of the apps above, or convert the file to a format your existing software already reads. If double-clicking opens the wrong program instead of nothing at all, the file association is set to the wrong app rather than the file being broken.
The other possibility is that the file is not really a .part at all. Drop it into the file identifier to check it by its bytes instead of its name. Nothing is uploaded.
PART has no fixed magic number, so there is no signature table on this page. Its bytes alone do not prove the format: identification relies on the extension, the structure of the content and the program that created it. The magic-numbers reference lists the formats that do carry one.
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. How sources are ranked and what is deliberately left out is set out in the methodology.