And how exactly do you use an external drive? Due to the limitations of the internal drive, I have used quite a variety of external drives with my iMac, but no solution is really good and all are much inferior to an internal drive. USB 3 drives work the best, but are limited and speed as is the number of USB ports on the mac. Going via hubs is possible, but reduces the reliability of the connection, I keep getting drive disconnects. Also, I haven't really been able to find a reliable Thunderbolt 2 drive.