Manatee

How to repair a corrupted GoPro or drone video on a Mac

· 7 min read

Action camera and drone clips that will not open on a Mac are nearly always files the camera never finished writing: the battery died, the card filled, the camera overheated or the card was pulled before the index at the end of the file was saved. The video frames are on the card; the table that tells a player where they are is not. Let the camera try its own repair first, copy everything off the card without reformatting, and then rebuild the index on the Mac. A repair typically gets back everything up to the moment recording stopped.

Why these clips break more than phone videos

A phone writes to fast internal storage and shuts down gracefully. A GoPro on a helmet or a drone at 300 feet is writing a high-bitrate MP4 to a microSD card while running hot on a battery that can cut out, and it stops recording for reasons it cannot plan for. Common triggers:

  • Battery removed or exhausted mid-clip.
  • Card full; some cameras handle this cleanly, some do not.
  • Thermal shutdown in direct sun or at high bitrates.
  • A card that is too slow for the chosen resolution and frame rate, which causes dropped frames and, eventually, a write failure.
  • Card pulled, or the camera powered off by a button press, while the file was still open.
  • A crash landing, on the drone side.

The result is an MP4 (or MOV on some drones) with a full data chunk and no moov atom, which is the index players need. Finder shows a file of the right size, QuickTime says it cannot be opened, and every editor refuses it. Phone clips fail the same way far less often, which is why the fix for these feels unfamiliar. The mechanism is the same as in how to repair a corrupted MP4 that won’t play on a Mac.

Step 1: let the camera try first

Both GoPro cameras and DJI drones attempt to finalize an unfinished file the next time they power on with the card inserted. This is the single most effective repair available, because the camera knows exactly how it was encoding.

  1. Put the card back in the camera it came from, if you have removed it.
  2. Power the camera on and leave it alone. A GoPro may show a repair icon and take a minute; a drone may do the same on startup.
  3. When the camera reaches its normal screen, play the clip back on the camera or through its app.
  4. If it plays, copy it to the Mac normally.

Do not reformat the card, and do not record new clips onto it until the damaged file is safely copied; new recordings can overwrite the unreferenced frames.

Step 2: copy everything off the card

Use a card reader, not a cable to the camera, and copy the whole DCIM folder, not just the one clip.

GoPro writes sidecar files beside each MP4: a .LRV low-resolution proxy and a .THM thumbnail. The LRV is a complete, separate recording at low resolution, and because it is written alongside the main clip it sometimes survives when the main file does not. Rename a .LRV to .mp4 and it plays. It is not the footage you wanted, but it is the footage.

DJI drones write a .SRT file with flight telemetry next to each clip; keep it if you overlay that data.

Check the size of the damaged clip in Get Info. A 4K clip at high bitrate is roughly a gigabyte a minute, so a ten-minute flight that shows 60 MB recorded only a few seconds before failing. A clip of the right size contains the frames and is worth repairing. A 0 KB clip contains nothing; see video file is 0 bytes or shows the wrong length.

Step 3: check whether it is a playback problem rather than corruption

Before repairing anything, make sure the file is actually damaged and not merely encoded in a way your Mac will not play.

  1. Open Terminal, type file with a trailing space, drag the clip in, press Return. “ISO Media, MP4 Base Media” with further detail means the header is readable.
  2. Try QuickTime Player (File, Open File), then Quick Look (select the file, press Space).
  3. If the clip is HEVC (GoPro’s higher modes and most DJI drones record HEVC by default) and the Mac is a 2016 or earlier model or on an old macOS, playback may fail or stutter even with a perfect file. Converting to a standard MP4 solves that; see H.264 vs HEVC: which one your Mac, phone and recipients can open.

Step 4: rebuild the index with Manatee

If the camera’s own repair did not work, Manatee does the rebuild on the Mac. Drag the clip onto its menu bar icon or into its window, choose Repair, and it reads the raw video and audio data, reconstructs the missing index, and writes a new playable file next to the original. The original is never modified, so you can try other approaches later if you want to.

The outcome is reported honestly. Fixed means the whole clip came back. Partial means the clip plays up to a point (for example, the first eleven minutes of a fourteen-minute flight, if the card stopped accepting writes before the camera stopped sending). Not fixable means the file held no decodable frames. What Manatee cannot do: recover footage the camera never wrote, restore a clip deleted from the card (it is not an undelete tool), or repair the card itself. Everything runs on your Mac, nothing is uploaded, which matters for gigabyte-scale clips on a hotel Wi-Fi. It is free for 24 hours with every feature, then $9 once.

Once the clip plays, Manatee’s Convert mode writes a standard MP4 for editors or recipients that choke on HEVC, and Shrink will bring a multi-gigabyte flight down to a size you can send: name a size in MB and it picks the quality that fits.

Step 5: the frames that play but look wrong

A clip that plays with blocky smears, frozen sections, or audio drifting out of sync was recorded with dropped frames, usually because the card was too slow. That is not corruption in the file-structure sense and a repair will not change it; the bad frames are bad on the card. Your options are to cut around the damage in an editor or to accept it. Going forward, use a card rated for the camera’s bitrate (check the camera maker’s recommended list) and format the card in the camera rather than on the Mac.

Questions

The repaired clip plays but the last minute is missing. Can that be found? Usually not. The camera stopped writing at that point, often because the card stopped accepting data a few seconds before the camera noticed. The repaired file contains every frame that reached the card.

My GoPro shows the clip in its gallery but the Mac cannot play it. The camera may have repaired it in place (Step 1) after you copied it; copy it again. Or the file is HEVC and the Mac is struggling with the codec rather than the file; try converting it.

Does reformatting the card make recovery impossible? Formatting in the camera usually only rewrites the file table, so specialized undelete tools can sometimes find clips afterward. Manatee does not do that. Stop using the card immediately if you need a deleted or formatted clip back.

The drone’s MOV file opens but the SRT telemetry does not line up. The SRT is timestamped to the original recording. If the repaired video lost its first seconds, or the camera’s repair trimmed it, the offset will be off by that amount. Most editors let you slip the subtitle track to match.