QTR-Quadtone RIP

I recently decided to take another run at QTR and wanted to install/create printers. Short version: it wouldn't work. I kept getting error reports and no printers.
Since no one is going to install all that many QTR printers with any regularity, I will simply report the solution, without bothering to track down the exact cause.
If you can't install a printer, restart your Mac while holding down the Shift key (no startup items and extensions off). Install the printer, then restart normally.
Have fun.