lenovo hangs on boot when usb drive is connected

[compdoc]

> I'm using 14.04.2 on a lenovo that I remotely administer. I have an 
> external drive attached for backups - has .tar.gz files no OS not 
> bootable. Nonetheless it hangs on boot if the external unit is 
> connected

I've seen this happen with computers not running Ubuntu. I think that some
computer bioses prioritize a usb device found during boot.

To solve the problem I made sure that the USB device was attached to the
computer when the computer is turned on, and then in the bios setting the
boot order to only include what I want the PC to boot from.
(excluding/disabling the usb device from the list)

Of course, if you attach a different usb device later, you might have to go
through this same process again.