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.
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. By design, OBS can only write the moov atom after recording finishes and the file is finalized.
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
Some interrupted files can be salvaged with a simple FFmpeg stream copy, which attempts to re-wrap whatever readable data exists into a fresh container. On its own this works roughly 40% of the time — usually on files where only the very end was cut off. It's worth trying first because it's fast and requires nothing else.
StreamSalvage runs this step automatically when you drop a file in, and tells you whether it succeeded before you do anything more involved.
Step 3: Use a reference clip (the method that actually works)
This is the technique that takes success rates from ~40% to around 85%, and it's the part most people miss. The idea: 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 |
| Guess whether it worked | 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
Once your file is recovered, change two OBS settings so a crash can't ruin a recording again:
- Record to MKV, then remux to MP4. MKV stays playable even if OBS crashes mid-recording, because it doesn't depend on a final index. OBS can remux it to MP4 afterward with no quality loss.
- Or enable fragmented MP4 in OBS output settings, which writes the index incrementally so a crash leaves a still-readable file.
Either option means the worst-case outcome is a recording you can still open — no repair needed.
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?
For the highest success rate, yes. A reference clip recorded with the same resolution, frame rate, and encoder as the broken recording gives the repair a matching template to rebuild from, pushing success rates to around 85%.
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.