I have seen all the previous posts that suggest how to feed the envelopes and to select envelope #10 on the printer itself. I have tried that and also made sure in Word that Envelope 10 is selected. Nothing works! My printer always printed envelopes correctly before, but now for some reason whenever you properly load envelopes its comes back and says there is a paper mismatch and it's expecting plain paper, letter. This is even after the printer knows you've selected #10 envelope!