I have a 1. 5 Tb usb drive that will not mount over the network. It mounted twice for me and when the computer is asleep and then wakes up again, the Apple TV will not mount to the drive. I receive the error that the volume has failed to mount. The drive is formatted Fat32 and it is hooked up through my Mac Mini.
If your computer is going to sleep regularly it’s best to unmount the volume from the AppleTV. This can easily be done by highlighting the drive through the nitoTV --> Files menu and pressing the left arrow (<<) button.