Hi guys, My late 2006 iMac internal hard drive has failed again. And since it's such a pain in the *** to open the case and replace the HD i have decided to boot from a usb3 external drive. It's certainly much slower but it works. My problem is that after a while (1/2hours, hours, its unpredictable) the drive seems to stop being readable and everything on the mac needing to read from the hd becomes unresponsive. Finder in the first place. I have tried unplugging then replugging the external HD with no success. It's like the mac would tell the hd to sleep at some point but the later would never wake. Someone has an idea? Thanks for your help !!