I'm using OS X 10 13 High Sierra and have an number of drives that I encrypted using Disk Utility when formatting them (none via TimeMachine). Couple of questions:
I can't determine which are/aren't encrypted - how to determine?
One encrypted drive comes up with a dialog asking to enter the password when my MacBook starts, but its in keychain. So if I enter the pw again it says its already unlocked. The dialog is annoying and only happens with this one drive.
Can I only encrypt a drive on formatting it or can I encrypt it when it already has files on it?