Problem with encypting an external hard drive
I copied some files to an external hard drive (formatted OS X Extended) that is connected to an iMac, right-clicked on the volume on my desktop, chose the encrypt option, and created a password. Now the iMac can no longer mount the drive. If I unplug and replug the drive, I can enter the password, but then get a message that the drive is not readable by the computer, along with an option to initialize, which opens disk utility.
What happened here? Can you not encrypt an external hard drive without first erasing it? Is there no way for me to now get the drive to be readable again without first erasing it?
iMac, OS X 10.11