I've been leaving my external HDD mounted and running almost continuously lately b/c I've been trading and transferring large files. Twice in the past three days it's locked up completely, and I can only unfreeze the entire system by powering it off completely. I've verified the disk using Disk Utility, and everything checked out pretty well there. Is there something else I should do to make sure it's not about to crash, or should I just turn it off so it can cool down at night and stuff? Thanks for any help anyone can offer.