I am running Lion on a 2011 MBP and 10.6.8 on a 2009 MB unibody and printing wireless with a Brother HL-2170w. I have had no trouble using this printer until today, when randomly both macbooks say there is software missing and I need to install it via apple. I hit the "find software" prompt and after a minute or so it says "operation could not be completed, no more information on this problem available". I downloaded the Brohter printer driver set from apple.com, but had no luck with those. I am getting frustrated at this point as I cannot find any info on the web about similar problems. Any ideas? I have not yet tried to print through usb.