I'm thinking this is some kind of system bug I've got on my iMac (27" 2.93GHZ i7). I keep a few drives connected at all times, and every now and then one of them becomes 'unwriteable'. I run Disk Utilty on it, all I generally need to do is just verify the disk, and it's back to normal. But it keeps happening, and at one time or another to any of the drives that are attached. Anybody have an idea what could be causing this/what I should do to troubleshoot/make it stop happening? thanks!