“cannot open” when trying to save screen recording in quicktime player After choosing a file location to save a screen recording, the movie will start to save, then it says "Cannot Open" and nothing is saved. I can retry but it still doesn't. I just saved a video before this. It's on macOS High Sierra. 10.13.1. This same issue is plastered all over the Apple.com help forums but there are no answers.

QuickTime is Version 10.4 (928.5.1) - the version that came with my MacBook Pro (15-inch, 2016).

After the saving progress bar gets to about 1/4, it flashes "cannot open this media may be damaged quicktime" then "Cannot Open"

I'll add a video below to show exactly what 

To debug, I did confirm that a 5 second video with voiceover could save. However, a 25 minute video will not. I closed that video and recorded another screen recording for 10 minutes long and same issue. In the past I've been able to record 10-30 minute videos and save. Now it only allows small videos.



Video of what happens: https://www.youtube.com/watch?v=DBME45Ks3_o
Sounds like a permissions problem. If it’s a bug I suspect it will be fixed in a future macOS update. Not much help, I know.

Until then, you have to peek behind the curtain:


Unsaved recordings are stored at ~/Library/Containers/com.apple.QuickTimePlayerX/Data/Library/Autosave Information/
The file will be called Unsaved QuickTime Player Document.qtpxcomposition, or similar
Show Package Contents on that file
Inside is Screen Recording.mov which you can copy and keep