"moov atom not found": a video file that won't play or was cut off
Last reviewed 2026-09-19
An MP4 or MOV file has an index (the moov atom) that maps every video frame and audio sample. Cameras and phones write it last. If recording stops early, the picture data is in the file but the index is missing, which is why players say the file is invalid. Whether it can be repaired depends on whether the index survived.
Messages you might see
- “moov atom not found”
- “Invalid data found when processing input”
- “This video file cannot be played (0xc00d36c4 / can't open file)”
Why it happens
- The recording was interrupted (battery, card full, crash) before the index was written.
- The file was copied or downloaded only partly.
- The index is at the end of the file and the end was cut off.
Try this first (free, no tool needed)
- Check the camera folder for a smaller proxy or low-resolution copy of the same recording (GoPro .LRV, DJI .SRT companions and similar).
- If you have a working clip from the same camera with the same settings, tools such as the open-source untrunc use it as a template to rebuild a missing index.
- Try VLC or another player before repairing. Some cut-off files open partly.
- Stop recording to the same card and copy the file off before anything else.
If that didn't work
These tools run in your browser. Your file is read and repaired on your own device and is never uploaded.
Corrupted MP4/MOV Repair
Works when the index is still there: it trims an intact index to the frames that really are in a cut-off file and corrects the durations, and fixes missing ftyp, junk at the end and wrong media size. If the index itself is missing or cut off, it tells you so and explains what would be needed, rather than guessing.
Open Corrupted MP4/MOV RepairCorrupted GoPro/Drone Footage Repair
The same repair aimed at GoPro, drone and action-camera clips, with an option to remove telemetry and timecode tracks that some editors choke on. It cannot join numbered chapter files.
Open Corrupted GoPro/Drone Footage RepairCommon questions
Why can't you just rebuild the index from the picture data?
Frame boundaries inside the data depend on the encoder's settings. Rebuilding them needs a working reference clip from the same camera, which a single broken file cannot provide.
Is my file uploaded anywhere?
No. The tool runs as a program inside your own browser, so the file is read and repaired on your device and never sent to a server.