USB failures? Consider USB selective suspend setting
Just want to toss this out there. A number of people have reported problems here and there with backups failing to USB devices.
There is a power setting called USB selective suspend setting. If you are having USB issues, it might be worth trying to disable this setting (if it was enabled) to see if that helps.
Go to Control Panel->Power Options->Change plan settings->Change advanced power settings
I once created a power plan called Keep Running than basically does just that... it keeps the system fully running.. Then, it is very easy to just change the active power plan as needed.