I naively bought a Seagate Backup Plus drive 'for Mac' a few months ago to use as a time machine for a 2009 MBP. It doesn't work. If I get it to be recognised at all, it lasts a few minutes before it ejects itself. Same on my 2010 iMac. It does work perfectly, however, on a 2012 Retina MBP so it's not dead. I'm assuming this is a USB 3 issue. What USB 2.0 drives would you recommend? I tend to go to Samsung for this stuff, but thought I'd check. We only need 500-1000GB storage.