I had OS 10.6.8 (Snow Leopard) on my 2010 macbook pro and had to buy a back up disc to store everything before updating to el capitan & it worked for me. After I updated my OS, I repeated the backup. You can always ask Geek Squad in the store or the apple support online re: your concerns.. BTW, my external drive says it is compatible with OS10.9 or higher, not 10.7. Also the usb connector works for both usb 2.0 & 3.0 ports.