I had this question, too. I called Apple and spent an hour with a rep trying to fix it. He suggested deleting the printer and then re-installing it. It was impossible to reintstall the printer. I could ping it, so it was physically connected for sure. It would not show up in the printer list. I gave up for the day but called a day or so later, got another rep, tried the same steps, no luck. The rep escalated the problem to a senior advisor, who also tried, then gave up and told me to call HP. Next day I tried on my own again and succeeded. The error made by the Apple reps was in not selecting the right type of printer to be displayed. You cannot just go with the LPD default option. In this case I just had to specify the HP printer that showed in the alternatives. I called HP anyway, and the rep said that they had received a number of calls about this problem. He asked for permission to access my Mac remotely, logged in, did several deletions and downloads, and solved the problem. Very knowledgeable guy, very pleasant and helpful. My advice, call HP business subunit 1 800 334 5144 . I was very disappointed in the response of the Apple reps -- previously they have been excellent. Interestingly, this occasion was the first time that a conference with an Apple rep was not followed by a request for an evaluation of the session. Guess why. I have also talked to senior reps at Apple who were wizards, also logging in remotely to resolve a difficult problem. Good luck!
