I have an external USB 3.0 HDD that I only use for weekly backups. I usually just leave the usb cable connected to the computer and plug it into the power socket when needed, do the backup, then eject it via Windows (10) and after a few minutes (I wait for it to go to sleep for a while - it usually doesn't stop spinning for many minutes) I unplug it only from the power (220V) but not from USB.
Will leaving the drive connected to USB affect it (or the PC) in any way? Does it know not to use the USB power at all to try to spin up? I'd imagine the USB doesn't supply enough power so it could technically damage the motherboard?
The reason I'm not also disconnecting the USB is because the drive is connected to a port on the back of the computer so I either have to get below the desk with a flashlight to find the right cable and port (when inserting...) or move a few boxes to get to the back of the drive and disconnect the flimsy micro-usb-B connector (the extra wide one).
