4K 29.97 video files corrupted by Sony mirrorless?

 I shot two half hour clips  at 4k 29.97 with a Sony A6500.  The camera was a unmanned lockoff.
One of the files is unreadable by FCPX or quicktime and the other one plays back in slow motion with no audio. It is over 2 hours long even though it was shot closer to half an hour.
Get info shows them as normal in Finder. Does anyone know  what  might have happened?

What version of FCP are you using? What format did the camera shoot?

You can try VLC player. My team has one of those cameras and the only time we had a similar problem was when the battery died and it shut down during a take.

If you still have the SD card, put that back in the camera and see if the camera can read it. Sometimes the camera can itself can fix some simple problems. If the camera can read it, consider transferring the files via USB from camera to computer.

If that doesn't work, beyond just trying it in the camera, don't try other data recovery methods until you evaluate how important the content is. A professional data recovery service can often recover that, but not if you mess it up by trying different things.

Thanks for  your response!  Great suggestions.  I found out the camera was somehow inadvertently set for slow  motion 120 fps 1080p when we changed the battery.  I tried retiming it back to original length but it's very noisy
looking.
    I put the card back in the camera and the other clip is not there. I'll try professional recovery for the missing
 clip.  I know it was recorded but got lost somehow. That was a very costly battery change. Losing the wide shot
on a 3 camera concert shoot.

Might check the AVCHD folder. Battery died on my Sony and thought I lost the footage. Saw it playing in camera so I knew it was there somewhere. Turns out the camera mode mysteriously switched to AVCHD and I NEVER shoot that so somehow something got discombobulated and I wound up with a weird file type I specifically avoid.