(I had it on the table next to the computer and with very quiet computer gave out a horrible buzzing sound). and try to keep it open which keeps it spinning. You can also mount the USB drive in Finder. a lot less cheap for USB3 which still might be a better buy into the future. USB powered hubs are very cheap for USB2. a powered hub can sometimes control things better. The one thing that is worthwhile is to use a powered usb hub. different disks, different controllers, different USB chips. And it is no use telling you this brand works and this one doesn't because the manufacturers change the insides of these regularly. you will need to hunt through a dozen different brands of USB drives. but the noise drove me up the wall eventually. and that kept it active for Time Machine. having the same experience I forced the drive to keep spinning. There is very little you can do to fix it. and all is well until the next spin down. The reset causes the drive to spinup again. so it will just sit there dead as a door nail. The drive will often spin down and not pickup the spinup command. USB drive plugged into the TC (or Airport Extreme) is at the end of a chain.
