What to do right now
- First open it in another player such as VLC to rule out a codec problem.
- Leave the original alone and work on a copy on another disk.
- Check the structure to find the cause, then use the matching repair.
How to fix it, by cause
Check the player and codec
Sound without picture, or a message that the format is not supported, usually means a missing codec. H.265 (HEVC) video from phones needs the HEVC extension on Windows. If another player shows it fine, the file is not damaged.
Check the structure
Add a copy to FileFix Ultimate's damaged file repair and inspect it. It reports problems such as a missing moov index, missing media data or truncation.
Repair a truncated MP4
For a file cut off during copying or missing its end, version 1.0.4 fixes the index so it plays up to the data that remains and saves it as a new file.
Repair an interrupted recording
A file with no index at all gets a new one built from a normal clip shot on the same device with the same settings. Follow the guide on repairing interrupted recordings.
Judge fragmented recoveries
If a recovered video shows scenes from another video, it was fragmented on the disk. Usually only the beginning is correct, and keeping that part is the realistic goal.
Reading the symptoms
A file that will not open at all and shows zero or unknown length is most likely an interrupted recording without an index. A file that plays and then stops at one point is truncated. A file that plays but breaks up or shows unrelated scenes partway through has other data mixed in from the recovery.
A file with a few bytes changed by a transfer error usually breaks up only in that section and recovers at the next key frame. Most such files are still watchable as they are.
What repair can get back
Repair fixes the index and structure so the remaining video data plays again. Video data that was overwritten or never written cannot be created by any tool. The result is a new file, honestly labelled with its validation status.
When repair will not work
- The video data itself was overwritten or never written.
- It is an interrupted recording and no reference clip from the same device and settings exists.
- Structure repair is not supported for formats other than MP4 and MOV, such as MKV or AVI.
- The video is encrypted or DRM-protected.
How FileFix Ultimate helps
- Inspects the box structure of MP4 and MOV files and reports the cause.
- From version 1.0.4, repairs truncated MP4 files and interrupted MP4 and MOV recordings into new files.
- Goes deeper with FFmpeg's ffprobe if it is installed.
- Never modifies the original and labels results honestly.
FileFix Ultimate is free, works offline and never writes to the drive you are recovering from. Check the signature before you run it.
Frequently asked questions
Is there free software to repair corrupted video?
FileFix Ultimate is free, and from version 1.0.4 it repairs truncated MP4 files and interrupted MP4 and MOV recordings.
The video plays sound but no picture.
Usually a missing codec. Install the HEVC extension or use a player with built-in codecs.
A recovered video shows another video halfway through.
The file was fragmented on the disk and other data got mixed in. Only the correct beginning can be kept.