OBS recovery guide
How to fix a corrupted OBS recording when the MP4 won't play
You finished a long stream, OBS crashed or you ran out of disk space, and now you're staring at an MP4 that refuses to open in any player. The good news: in most OBS-crash cases the video and audio are still inside the file — only the part that tells a player how to read them is missing. This guide explains exactly why that happens and walks through how to repair it on Windows.
Check the file before choosing a repair
- 0 bytes: there is no video data in that file to rebuild. Look for another recording, backup, or recovered copy first.
- MKV or a readable fragmented MP4: try OBS File → Remux Recordings on a copy. You may not need a repair tool.
- Plays in VLC but not another app: check player and codec compatibility before treating the recording as corrupt.
- Non-empty standard MP4 with a missing moov atom: preserve the original and try the matching-reference approach below.
How to recover an unfinished OBS recording in MP4
For an unfinished standard MP4, first preserve the non-empty original. If OBS or FFmpeg cannot read its metadata, repeating a remux will not finish the recording. Try a matching reference clip, then check the recovered duration and each audio track. The steps below explain that workflow.
“Recording remuxed, but the file may be incomplete”
This OBS warning means you should verify the output before relying on it. Keep the source recording, check free space in the destination, and compare the source and output duration, picture, and audio tracks. If the original MKV plays, preserve it and investigate output-format or codec compatibility before attempting MP4 reconstruction.
The warning appears in OBS's remux messages. It does not by itself identify missing MP4 metadata. Our FFmpeg input-error guide explains how to check which streams remain readable.
Why an OBS recording becomes corrupted
An MP4 file stores a small but critical index called the moov atom. It records the timescale, duration, and the location of every frame — essentially the table of contents a media player reads first. With standard MP4 recording, OBS writes the final index when recording stops. Hybrid MP4 and fragmented MP4 use a different structure that is more resilient to interruptions.
If OBS crashes, your PC loses power, or the disk fills up before that final step, the recording is never finalized. The raw frames are written to disk, but the moov atom never gets created. The result is a file that is mostly complete yet completely unplayable, often producing a moov atom not found error.
The key insight: a missing moov atom is not the same as lost footage. The frames are usually right there on disk — the file just has no index pointing to them. That's why these recordings are so often recoverable.
Why VLC and a simple re-open won't fix it
VLC is excellent at playing through minor glitches, and people often try it first. But VLC can only work with an index that exists. When the moov atom is missing entirely, there is nothing for VLC to rebuild from — it can't invent the map of where each frame begins. The same is true for "just rename it" or "convert it" tricks: without the index, a converter has no frames it can confidently read.
Step 1: Stop and protect the original file
Before anything else, make a copy of the broken recording and work only on the copy. Repair attempts should never overwrite your one surviving file. Note the exact OBS settings you recorded with if you can remember them — resolution, frame rate, and encoder (x264, NVENC, etc.). You'll want these in a moment.
Step 2: Try a straight stream-copy repair first
If FFmpeg can read the file and identify its streams, a stream copy can remux the readable media into a new container without re-encoding. It cannot rebuild a completely missing moov atom. If it reports that error, move on to reference-assisted repair.
In StreamSalvage, select the broken file and choose whether to provide a reference before starting the repair. You can inspect the preview if a repair succeeds.
Step 3: Try repair with a matching reference clip
A reference clip can help a repair tool interpret surviving media when the original index is missing. Recovery depends on the file damage and codec support. To try it, record a short, clean clip using the same OBS settings as your broken recording. Because it finalizes correctly, that clip contains a healthy moov atom built by the exact same encoder. That healthy structure becomes a template the repair uses to rebuild the missing index in your broken file.
- Open OBS and load the same scene/encoder settings you used originally.
- Record about 10 seconds, then stop so the clip finalizes normally.
- Provide both the broken recording and this reference clip to your repair tool.
- The tool maps the reference's metadata onto your broken file's frames and writes a new, playable MP4.
Matching matters. The closer the reference clip's resolution, frame rate, and encoder are to the original, the higher the chance of a clean repair. A mismatched reference can still work but often produces audio/video sync issues.
Doing it the manual way vs. a one-click tool
The open-source tool untrunc implements this reference-based repair and is free, but it runs from the command line and can be intimidating to build and use. If you'd rather not touch a terminal, a dedicated app does the same thing with drag-and-drop. We compare the two in detail in our untrunc alternative guide.
| Manual (untrunc CLI) | StreamSalvage |
|---|---|
| Build and run from terminal | Drag and drop |
| Open the output in a player to check it | Free preview before you pay |
| Local, but technical | 100% local, no command line |
| Free | $29 one-time to export |
Repair your corrupted OBS recording
Drop your broken MP4 in, preview the repair for free, and only pay if it works. Everything runs locally — your footage never leaves your PC.
Download StreamSalvage for WindowsHow to prevent this next time
Reduce the risk of another interrupted recording by choosing MKV and remuxing to MP4 afterward, or using Hybrid MP4 if your OBS version offers it. Keep adequate free disk space and test playback in your editor.
See our OBS MKV, MP4, and Hybrid MP4 comparison and OBS's explanation of Hybrid MP4. These formats improve resilience; they cannot protect against every drive failure or recover data that was never written.
Frequently asked questions
Can a corrupted OBS MP4 with no moov atom be fixed?
Often yes. If OBS crashed before it could write the moov atom, the audio and video data is usually still intact — only the index is missing. Using a short, clean reference clip recorded with the same OBS settings, the missing metadata can be rebuilt and the file made playable again.
Why won't VLC fix my corrupted OBS recording?
VLC can sometimes play through minor damage, but it cannot rebuild the moov atom that OBS never finished writing. When the metadata that tells a player where each frame lives is missing entirely, VLC has nothing to play from.
Do I need the original OBS settings to repair the file?
A matching reference is useful when the recording is missing metadata. Match the resolution, frame rate, video encoder, and audio settings as closely as possible. A reference cannot restore frames that were never saved, and a successful repair is not guaranteed.
Will repairing the file upload my video anywhere?
It does not have to. StreamSalvage repairs the file entirely on your own PC, so private footage never leaves your machine and there is no slow upload for large recordings.