I am having trouble printing #10 envelopes from the priority feeder. I have the paper size set to #10 envelope, landscape. But the envelope prints as though it is an 8 ½” X 11” piece of paper (left side of feeder). It will pick up the envelope from the priority feeder but report a paper size mismatch and ask if it is OK to use the #10 envelope and then shift the print so far to the left (top of envelope) that the senders address is missing and the recipients address is at the very top of the letter. The only thing that I have found to work is to load HP Utility and tell it that Tray1 is #10 envelopes, print the envelope, and then reload HP Utility and change tray1 to Letter.