Greetings all, I've always used time machine to back up my Mac, but recently my wife and I both got new Macs (an iMac for me and a MBP for her). We each have separate backup drives for our computers, but recently I decided to buy an extra 4TB drive to hold duplicate backups. My plan is to keep that drive at work (in case of fire or something else that could wipe out computers and backup drives) and just bring it home once every couple weeks to update the backup. I set up the drive yesterday but don't remember the formatting I used. I plugged it into my wife's MBP and set up the disk as a new time machine backup drive. At some point in this process I was asked if I wanted to encrypt the backups and thought that sounded like a good idea, so said yes. The actual backup of the computer didn't take too long (a few hours for ~120GB), but the encryption has been running for at least 20 hours and is only about 80% finished. I understand that the encryption will probably take much less time with future incremental backups, but the whole situation has me a bit puzzled about my approach to backups. Is it a bad idea to be backing up both of these computers to the same 4TB drive? The iMac has at least 500GB of data and could conceivably take days to backup and encrypt on the first pass (although it should be faster due to a much better processor). My normal backup drive for the iMac has a password for the disk that one must enter to access the drive, but no actual encryption. I assume this is better than no password and no encryption, right? Should I encrypt the backups on that drive as well? I'm not overly concerned about the encryption time on the new drive, but just want to make sure that this makes sense and that it's worth the wait. Am I correct to assume that future backups will be much, much faster? I think I have a cursory understanding of encryption but just want to make sure I'm being logical. Any tips on drive formatting or anything else involved are very welcome. Thanks!