We have recently enabled the guest account for a group of 1-to-1 iMacs in our environment so that the computer can be used by a substitute when the primary user is gone. The issue we're running into is that some, but not all, computers are going to the lock screen and asking for a password after they sleep. Our guest account doesn't have a password and simply pressing enter doesn't unlock the computer. Has anyone else run into this or something similar? We can't seem to find a difference between the computers that go the lock and those that don't.