I installed a new Brother HL 2270 laser printer yesterday, exclusively to print duplex copies of a 120 page thesis. The test-run worked well, but when I tried to print 25 minutes later, the "print two-sided" option had disappeared from my print options. Not grayed-out, just gone completely. I'm printing from a Macbook Pro, using OS 10.7.3 Any ideas? If not, do any laser printers have a reputation for good driver interoperability with macs?