I've found out what was causing this. The .minecraft folder and it's content were somehow changed to read-only. This report can be removed. Sorry for any time I've wasted with this.
Screenshot after "Log in" Button is pressed. Launcher Freezes at this point.
Screenshot before "Log in" Button is pressed.
I can't login to the launcher and cannot access the devolpment console.
I've found out what was causing this. The .minecraft folder and it's content were somehow changed to read-only. This report can be removed. Sorry for any time I've wasted with this.