HELP - Unknown Error (-101)

[Sdahe]

Hello,

Suddendly my iMac started giving me this unknown error when trying to open a video. I'm also getting this wierd thing in my volume settings... all the volume up and it's mute..

The error says: The document "Test gopro on car.mp4" could not be opened. An unknown error ocurred (-101)

What could this be?

Here some screenshots







Thanks