If you are printing from MS Office, you would need to change whatever the other user did in Page Setup
None of the replies I read seem to have any effect on what I am seeing, or seem irrelevant. OF COURSE the contents of Tray 1 (MPT) are unspecified, because it is SUPPOSED TO BE EMPTY. I read one reply which told me that I should use the "Administrative" tab to set Tray 1 to "Dynamic". I have no idea what antique version of the software this is referring to, but I cannot find an administrative tab, or anything resembling it, even when logged into my administrative account; I can find nothing about setting trays to static or dynamic. I have the latest drivers. Nothing seems to help. No matter what I do, it keeps telling me that Tray 1 is empty. After spending some time on this problem this afternoon, I have made it worse, because even if I explicitly select-by-tray Tray 2 (Letter), it now insists on using Tray 1. What is going on here? How can I get this printer to start working again? (A few weeks ago, another user printed some labels from the MPT. Now it won't acknowledge that any other tray exists). And yes, I have configured it for all the extra trays, and the hard drive. It knows the trays exist; it even knows what paper is in them (letter, legal, or tabloid). But it won't use them.