I'm putting this here rather than in Peripherals, since I think it's a Snow Leopard issue, meaning that I don't think there's anything wrong with my printer or its connection. Laserjet p2015dn. Always printed duplex when requested, although I can't say for certain that 10.5.8 worked, since I don't print duplex regularly. After SL, I had only the "Manual Duplex" option, and nothing I could do would return my standard Duplex option. I reinstalled, reset the printer firmware, etc. etc. Every place that there's a duplex option, it's checked. Everything else about the printer is fine -- it sits out on the network and prints happily. I have not made a USB connection to see if that makes a difference. Anybody else? I decided to post here before seeing what might happen if I reinstall the 10.5 package from HP (their site says -- don't do it).