Your GoPro stopped mid-recording and the MP4 won't open. Here is what to try, in order.
When a GoPro loses power or the card is removed during recording, the MP4 is left without the index that players need. The video data is usually still on the card.
Many GoPro models try to fix the last file themselves. Put the card back in the camera, with a charged battery, and turn it on. If the camera shows a repair message or icon, let it finish.
Copy the MP4 (often named like GX010244.MP4) and don't format the card.
Record a few seconds with the same camera and the same settings: resolution, frame rate, lens and HyperSmooth mode, and bit rate. A healthy clip helps rebuild the broken one.
FootageRescue's MP4 and MOV repair comes right after Sony .RSV, with a free 20-second preview before you pay. Join the waitlist to hear when it's live.
Need help with a specific file? Write to hello@footagerescue.com with the camera model and what happened.