I have a 500gb Western Digital external drive connected through a usb hub. Ever since upgrading to ML I periodically (maybe once every other day) get the "device did not eject properly" message. Out of nowhere my computer dumps the connection with the external drive. Sometimes the device will be eject while I'm using the computer, so it's not a sleep issue like some other users are having trouble with. Just now I was copying some a folder from the WD to my Dropbox desktop folder. In the middle of the transfer, it dropped the transfer and gave me the disconnect error. Any ideas what could be causing this? Fixes?