QuickTime Player Fails to Save Video

maybe your situation is differnet than mine was.

Check to see if Time Machine is backing up your system when you stop the recording.

Okay so I was having the same issue with QuickTime screen recordings and even lost a very valuable Skype interview due to the bug. Eventually I figured out what was happening. When I clicked stop recording and the new video didn't appear and the option to quit QuickTime grayed out I was invariably backing up my system with Time Machine. I have Time Machine set up to automatically back up my computer at regular intervals so I was not doing this intentionally, it was just a bad convergence of events. The first time I tested my theory out by just letting Time Machine finish it's thing and, voila, the video popped up as soon as Time Machine finished its back-up. The second time I tested it out by just clicking on the Time Machine icon and forcing the back-up to stop. The video instantly popped up when I stopped Time Machine. Most importantly the video and audio were both intact! This is not what happened with my Skype interview which I impatiently tried to grab from the temporary folder not realizing the hang up was due to Time Machine. When I moved the temporary file QuickTime could no longer find the file once TimeMachine stopped. I didn't notice this right away because I left my computer for a couple hours thinking the video was irretrievable. When I came back to my computer I had the error messages and the video worked but not the audio (the whole point of the interview). So goes it. I am glad to have noticed the Time Machine problem and hope it helps others.

Hi Paladin3,

I've had a similar problem before. I tried many things, but what did the trick for me was using a genuine Apple thunderbolt USB cable.. I'm not sure if it will solve your problem, but might be worth trying.

Good luck

An apple article is there : How to use QuickTime Player - Apple Support