Unidentified Developer Error (Mac users)
This error is not very common, but there's an extremely easy fix for this.
1) Go to System Preferences (Click the Apple logo on top left of the screen),
2) Click Security & Privacy (a home'ish icon),
3) Undo the lock at the bottom of the window so that you would access the complete menu (It may ask you for a password);
4) Under "Allow apps downloaded from:", check Anywhere.