How do I open a .filepart file?

You cannot — it is an incomplete download. Resume it in the browser or download manager that created it so it can finish and rename.

Can I just rename a .filepart to remove the extension?

No. The file is only partially downloaded, so renaming it will not produce a working file.

Is it safe to delete a .filepart file?

Yes, if you do not plan to resume the download. It only holds an unfinished, unusable copy.

Which programs make .filepart files?

Firefox and download managers like JDownloader use .filepart for in-progress downloads.

Can I resume a .filepart download from the command line?

Yes, if you know the URL. wget -c URL or curl -C - -O URL continues using the bytes already in the partial file, as long as the server supports range requests.

My .filepart is a video — can I watch what downloaded?

Often yes. Copy it, rename the copy to remove .filepart, and open it in VLC, which plays truncated media up to where the download stopped. This does not work for ZIP, ISO or installers.

Why does my .filepart restart from zero every time I resume?

The server probably does not support partial (range) requests, so each resume redownloads everything. Try a download manager or a different mirror.

What Is a .FILEPART File?

A download left a .filepart file and you cannot open it. It is a partial, unfinished download. Here is how to complete it or clear it safely.

What a .filepart file is

A .filepart file is a partly downloaded file. Firefox, JDownloader, and some other download managers write to a .filepart and rename it to the real name only once the download finishes. If you see one, the transfer did not complete. Microsoft Edge and some Chromium browsers write a .partial file for exactly the same reason, and Chrome uses .crdownload.

Why you have one

The download was paused, interrupted, or cancelled — a dropped connection, a closed browser, or a stopped download manager. The .filepart holds however many bytes arrived so far.

How to finish it: resume, by tool

You cannot open a .filepart directly — it is incomplete. The reliable fix is to resume in the same tool, so it appends the rest and renames the file:

Firefox: open the Downloads panel (Ctrl+J), find the stalled item and click the retry/resume arrow. Firefox keeps the .filepart next to the destination and continues into it.
JDownloader: right-click the link → Resume. It re-requests the missing byte range if the host supports it.
IDM / download managers: use Resume, not Restart — Restart throws the .filepart away and starts from zero.
Command line: if you know the URL, wget -c URL or curl -C - -O URL continues a partial download using the bytes you already have.

The source is gone — can I salvage the .filepart?

If the link expired and no resume is possible, a .filepart is usually a dead end — but there is one useful exception. For streamable media (MP4, MKV, MP3), the bytes that did arrive are often playable. Copy the file, rename the copy to remove .filepart (e.g. movie.mp4.filepart → movie.mp4), and open it in VLC, which tolerates truncated files and will play up to the point the download stopped. For archives (ZIP, ISO, installers) this does not work: a partial archive fails its checksum and will not extract. In that case, delete it and download again.

When a .filepart will not finish

If resume keeps failing or the file stays the same size, check in this order:

Server does not support ranges: some hosts refuse partial requests, so every resume restarts from zero. Switch to a download manager or try a mirror.
Disk full or quota hit: the write stops silently. Free space, then resume.
Antivirus quarantine: real-time scanning can lock or move the .filepart mid-write. Whitelist the download folder and retry.
Path/name too long on Windows: a very long filename plus .filepart can exceed the 260-character limit. Download to a short path like C:\dl\.

Is it safe to delete?

Yes, if you do not plan to resume. Deleting a .filepart just discards a broken, incomplete download and frees the space. Only keep it if you intend to continue the transfer. It is not a virus and never runs on its own — it is inert data.

How to handle a .filepart file by OS

Windows / macOS / Linux: behaviour is identical — resume in the download tool to finish it, or delete the .filepart to abandon it. Renaming it to strip .filepart will not repair an incomplete file (except the VLC media trick above).