When printing to my 7800 on our Mac OSX systems (all of them), it requires me to choose "Automatically Select" for both Paper Type and Paper Color in the print dialog's Printer Feature settings in order to print without getting a "resources required" error. I use cardstock for 11x17 and plain paper for 8.5x11 in the printer in different trays.
This extra step is required the first time I print from an application after it is launched, and then the setting sticks until I quit the app. This behavior is present in all apps, from Illustrator and Acrobat to Word and Safari.
On a related note, is there a way to tell the printer "just use any paper" when that @#$@#$ Resources Required error comes up that effectively kills my print job?
