Cannot change default MP4 player on Mac (error code 2

I Can Not Change The Default App Settings 

I’m trying to add a different Media Player than Quick Time Player as default.

When I try to change this At “Right Click - Get Info - Open With” 

I get this error;

You can't change the item “asdasd.mp4" to always open in the selected application.

The item is either locked or damaged, or in a folder you don't have permission to modify (error code 2).

OK

How can I do this?

The file is mp4.

The file path is Documents