Of course, if you force quit the application, the file won't work since it hasn't been properly finished. If you cancel the rip, it will close the file properly and it will work.
From my experience, it took a while at 100 percent for it to finish, even on small files of 3-7 minutes. On a 24 minute file, it took much longer. I can imagine with a 90 minute file that it would seem to take forever. You're best to go off and do something else rather than wait for it to finish. 😉