I've got a Dell 1130 laser connected via USB to my MacBook Pro running OS X Lion. The first thing I print comes out OK. Any subsequent print jobs are entirely ignored by the printer, although as far as OS X is concerned they're sent OK and disappear out of the print queue. The printer will warm-up as if about to print, but then just stop. The status light stays green, as if everything is OK. I've tried various things without success, including installing the latest printer driver from Dell's site, and using the Samsung ML-2525 driver (the Dell 1130 is a rebadged ML-2525), and updating the printer's firmware. Nothing fixes it. If I boot into Windows via VMWare Fusion and connect the printer to the virtual machine, it works fine. It'll print job after job without an issue. So I don't think it's a hardware fault anywhere along the line. A fix is to remove and reattach the USB cable after each thing I send to the printer, but this is a pain.