Video file is 0 bytes or shows the wrong length: can it be fixed?

These are two different problems with two different answers. A video that is 0 bytes has no data in it, and no tool can repair an empty file; the job is to find where the real data went. A video that is the right size but shows a duration of 0:00, or a wildly wrong length, or plays for less time than it claims, has a broken index, and that is one of the most repairable kinds of corruption there is.

If the file is 0 bytes

Select the file in Finder, press Command-I, and look at Size. “Zero bytes” means the file system has a name and no contents. This happens when:

• A copy was started and interrupted before any data was written (ejecting a card, a dropped network share, a cloud sync that failed).
• A recorder created the file and crashed before writing a single frame.
• A cloud service left a placeholder that was never downloaded. iCloud Drive and similar services show these with a cloud icon, and they download on open.
• An undelete tool recovered the directory entry but not the blocks.

There is nothing in the file, so stop trying to open it. Instead, look for the data:

1. Check the source device. Cameras, drones, and dashcams usually still have the original on the card. Phones have it in Photos.
2. Check whether the file is a cloud placeholder. If the file has a cloud icon, right-click it and choose Download Now, then wait.
3. Check the Trash and any other Macs or drives it was copied to.
4. Check Time Machine or whatever backup you use, if the file was ever on your Mac in a complete state.
5. On a memory card that still has the original, copy again, to the internal drive, and do not eject until the copy is done.

If none of those turn up a copy, the footage is not recoverable by file repair. An undelete tool that scans the card for video signatures is the last resort, and it only helps if the space has not been reused.

If the size looks right but the duration is wrong

Now for the fixable case. The file is hundreds of megabytes, so the frames are there, but the player shows 0:00, or 15 hours for a two-minute clip, or the right length with a progress bar that will not move.

MP4 and MOV files keep their timing in a table (the moov atom) that is written when recording stops. If the table was never written, players have no idea how long the file is and show zero. If the table was written with wrong values, which happens with certain recorders and with files that were concatenated or partially overwritten, players show a wrong length and get confused when seeking.

Either way, the repair is the same: scan the actual frames, measure their timing from the codec data, and write a new table. The Repair mode in Manatee does this.

1. Copy the file to your internal drive if it is on a card or external disk.
2. Open Manatee. The full app is free for the first 24 hours with no card or email.
3. Drop the video in, or right-click it in Finder and choose Fix with Manatee.
4. Wait for the job to finish, then read the outcome: Fixed, Partial (for instance “the first eleven minutes”), or Not fixable.
5. Open the repaired copy, written next to the original. The original is never altered.

Estimating how much is really in the file

Before repairing, you can predict the result with a bit of arithmetic. Most phone and camera recordings have a known bitrate:

• 1080p at 30 fps from a phone: roughly 8 to 17 megabits per second, which is 1 to 2 megabytes per second.
• 4K at 30 fps: roughly 45 to 60 megabits per second, about 6 to 8 megabytes per second.
• Screen recordings vary enormously and are often much lower.

Divide the file size by the per-second figure. A 1.2 GB 4K file holds about three minutes; if you were expecting ten, the recording was cut at three, and the repair will return about three. No tool can return more than the file holds. Partial recovery explained goes into why.

The half-copied file

A common variant: the file is the wrong size, somewhere between zero and what it should be, because a copy or download was interrupted. It shows the wrong duration because the index is either missing (written at the end and never copied) or present but pointing beyond the end of the file.

The approach depends on whether the source still exists:

• Source intact: copy it again. Every time. This gives you everything; a repair gives you a fraction.
• Source gone: repair. A file whose index sits at the front (“fast start” files from some cameras and most web-optimized exports) will often play up to the cut without help. A file whose index was at the end needs reconstruction.

File transfer interrupted: how to salvage a half-copied video covers this case in depth.

When the duration is wrong but the file plays

Sometimes everything plays fine and only the length is misreported, which is annoying in a video editor or when uploading. Causes include variable frame rate recordings (common from phones and screen recorders), edit lists left by editing software, and files joined from several recordings.

A container rewrite fixes this without touching the frames. Manatee’s Repair mode handles it; so does ffmpeg -i input.mp4 -c copy output.mp4 if you have ffmpeg in Terminal, since a remux recalculates the duration from the stream.

Questions

Finder says 0 bytes but the file took ages to copy. Where did the data go? Probably nowhere. The copy was writing to a temporary location or a cache that was discarded when the transfer failed, and only the empty directory entry remained. Check the source device for the original.

The video shows the right length, but the last half is frozen on one frame with audio playing. Is that the same problem? Related. The index promises frames that are damaged or absent in the second half. A repair will produce a file that is honestly shorter rather than one that freezes, which is usually better for editing and sharing.

Why does the Mac show a different duration from the camera? Cameras display what they intended to record; the Mac shows what the file’s index says. When the two disagree, the index is suspect, and the real answer is whatever the frames say, which is what a repair measures.

Can Manatee recover a video I deleted from my camera card? No. Manatee repairs files you already have. Recovering deleted files is a different task for an undelete tool, and it must be done before the card is used again.