QuickTime Player crashes on startup Suddenly I can't get QuickTime Player to work anymore because it crashes right after opening it. I do not know if this is the right error message from the log:

Application Specific Information:
Sandbox creation failed: Container object initialization failed.
NSCocoaErrorDomain:512


Does anyone know how to fix the problem or how to reinstall the application even if it's a system app?
As @Redarm suggested, you should remove the folder found at

~/Library/Containers/com.apple.QuickTimePlayerX


After that, quit and reopen QuickTime.