I have an old Lexmark Optra S 1620. When attempting to print from my mac os x 10.4 I get a message to load paper, regardless of the amount of paper in the tray, regardless of the program I'm printing from. Removing the tray and replacing it makes no difference. Adding a bit of paper makes no difference. Attempting to print a pdf from the net has occasionally appeared to trigger the problem. I used to be able to fix this by clearing the job, shutting down the computer, turning it on, turning on the printer again until ready. (Sometimes 5-10 times). I have removed and reinstalled the printer a number of times. That's never worked. Now I can't print at all from any program, any file type. Thank you for any information you have. I've called the printer dealer and they say it's a mac software problem, most likely, impossible to solve as the printer is so old.