When creating a bootable usb stick for Ubuntu 12.04 server edition, the startup disk creator pops up the "installation complete" window and another window titled "Upgrade volume detected" which says the following:
A distribution volume with software packages has been detected.
Would you like to try to upgrade from it automatically?
With options to
Run upgrade. What distribution volume is it talking about and where did it detect it? What does "upgrade from it automatically mean"?