The Unarchiver in my Macbook froze for the first time while I was extracting few RAR files at once. I could close the queuing files but not the one stuck in the unarchiving process.
I wanted to force quit it but it did not appear in the Force Quit list. Restarting the computer is one solution but my experience tells me it should always serve as the last resort and in most cases, it shouldn’t be considered as a solution at all. So how?
I found that just two UNIX commands can easily settle the problem:-
First enter top in Terminal and you will see a list of running processes on your system (just like the Activity Monitor). Spot for The Unachiver and its PID.
Then, enter the second command: kill -9 PID
Problem resolved! 
