Problem
Local recording uses a fragile format or container that cannot be recovered after a crash.
Solution
Root Cause / Diagnostic:
Standard MP4 and MOV containers require their file index metadata (moov atom) to be written at the very end of the file when recording cleanly halts. If OBS, the operating system, or power suddenly crashes mid-stream, the file index is never finalized, leaving the entire multi-gigabyte recording file unreadable and corrupted.
Actionable Fix:
1. Switch Recording Container to Fragmented MP4 or MKV: In OBS Settings > Output > Recording, set the Recording Format strictly to "Matroska Video (.mkv)" or "Fragmented MP4 (.mp4)".
2. Enable Automatic Remux to MP4 in OBS: In OBS Settings > Advanced > Recording, check "Automatically remux to mp4" so completed MKV files are instantly converted into standard MP4s for editing upon stream stop.
3. Test Crash Resilience with Task Manager Force-Kill: Perform a 5-minute test recording and force-close OBS via Windows Task Manager; verify that the resulting .mkv or fragmented .mp4 file plays back flawlessly up to the exact second of termination.
Pro Tip:
Fragmented MP4 (fMP4) writes movie fragments (moof boxes) incrementally every 2 seconds to disk; even if the computer suffers an instant power cut, 99.9% of your footage is immediately usable in Premiere Pro and DaVinci Resolve without repair tools.
Standard MP4 and MOV containers require their file index metadata (moov atom) to be written at the very end of the file when recording cleanly halts. If OBS, the operating system, or power suddenly crashes mid-stream, the file index is never finalized, leaving the entire multi-gigabyte recording file unreadable and corrupted.
Actionable Fix:
1. Switch Recording Container to Fragmented MP4 or MKV: In OBS Settings > Output > Recording, set the Recording Format strictly to "Matroska Video (.mkv)" or "Fragmented MP4 (.mp4)".
2. Enable Automatic Remux to MP4 in OBS: In OBS Settings > Advanced > Recording, check "Automatically remux to mp4" so completed MKV files are instantly converted into standard MP4s for editing upon stream stop.
3. Test Crash Resilience with Task Manager Force-Kill: Perform a 5-minute test recording and force-close OBS via Windows Task Manager; verify that the resulting .mkv or fragmented .mp4 file plays back flawlessly up to the exact second of termination.
Pro Tip:
Fragmented MP4 (fMP4) writes movie fragments (moof boxes) incrementally every 2 seconds to disk; even if the computer suffers an instant power cut, 99.9% of your footage is immediately usable in Premiere Pro and DaVinci Resolve without repair tools.