Device guide
Screen recording corrupted? The 4 GB trap and other fixes
You were capturing gameplay or a long session, everything looked fine — and the file came out "unsupported or corrupted." Two culprits cause almost all of these: the recording silently crossed 4 GB on storage that can't handle it, or the recorder itself crashed. Both leave repairable files.
Quick answer: a recording that broke at the 4 GB mark or in a recorder crash is an unfinalized MP4 — the data survived, the index didn't. Record a 10-second healthy clip with the same app and settings, then rebuild the broken file from it with a reference-file repair.
The 4 GB trap
FAT32 — still the default on many SD cards and some phone storage — cannot store a file larger than 4 GB. A screen recorder that doesn't auto-split hits the boundary mid-write, the write fails, and the file never gets finalized. The symptoms: a file sitting at exactly ~4 GB (or 3.99), "unsupported or corrupted" errors, and a recorder that seemed fine the whole time.
Everything up to the boundary is usually intact. Repair it like any unfinalized MP4 (below), and fix the cause: switch storage to exFAT, or enable file-splitting in the recorder settings.
Recorder crashes: phone apps, Bandicam, capture cards
- Phone screen recorders that crash or get killed by the OS leave a black-thumbnail, zero-duration file. Same repair path; see also the phone video guide.
- Bandicam has a built-in restore that often saves the video track but leaves audio corrupt — a full reference repair rebuilds both tracks.
- Capture cards (Elgato HD60 S etc.) during a BSOD produce files that half-play with glitches; a stream copy (
ffmpeg -i in.mp4 -c copy out.mp4) frequently cleans these up because the index survived. - OBS/Streamlabs crashes have their own guide: fix a corrupted OBS recording.
The repair, step by step
- Copy the broken file; work on the duplicate.
- Try the stream copy — it fixes the glitchy-but-indexed cases in seconds.
- Record a reference clip: 10 seconds, same app, same resolution/frame rate/bitrate preset. This is trivially easy for screen recordings — you control the recorder.
- Rebuild the index with the reference-file method and verify the output plays through with audio.
Repair crashed and 4 GB-capped recordings locally
StreamSalvage walks you through the reference clip, tries the quick fixes first, and shows a free preview of the repair — $29 one-time only if your recording comes back. No upload.
Download StreamSalvage for WindowsFrequently asked questions
Why did my screen recording corrupt when it reached 4 GB?
Storage formatted as FAT32 (common on SD cards and older phone storage) can't hold files larger than 4 GB. When the recording hits the boundary, the write fails and the file is left unfinalized — "unsupported or corrupted." The data up to 4 GB is usually intact and repairable.
Can I fix a screen recording that got corrupted when the recorder crashed?
Usually. A crashed recorder (phone app, Bandicam, or a capture-card session ended by a BSOD) leaves an unfinalized MP4. Record a short healthy clip with the same recorder and settings, then rebuild the broken file's index from it with a reference-file repair tool.
Bandicam restored my video but the audio is corrupt — why?
Built-in restore functions rebuild the video track's index but sometimes fail on the audio track's timing data. A full reference-file repair reconstructs both tracks from the template clip, which often recovers audio the built-in restore couldn't.
How do I stop screen recordings corrupting in the future?
Record to exFAT/NTFS storage (no 4 GB limit), set your recorder to split files into segments, keep ample free space, and on PCs record to MKV or fragmented MP4 where supported so a crash leaves a playable file.