Let me try again: After setting up a brand new iMac and in taking it for a test drive I looked at System Preferences/Security and followed the menu to encrypt. I said yes, set passwords and the process started. It has been overnight (19 hours so far) and I still see the black cursor circle spinning. How long should this take? I'm a 30 year PC user transitioning my wife to Apple and this is my first post here. Thanks!