I'm getting Ultigcode error messages when trying to print via usb on my Ultimaker 2+ with Cura 2.7. Can anyone offer a solution to this please ?
Go to the Printers pane of the preferences, and to Machine Settings. Change the Gcode flavor from "Ultimaker 2" to "Marlin". That will enable USB printing to the UM2(+), though it is still not recommended.