My solution for "Paper Mismatch" issue when printing envelopes

[IPFTA]

I followed all the online suggestions trying to get around the "paper mismatch" error on my printer (HP Officejet Pro 6975) using my word processor program (Softmaker's "Text Maker" ), but nothing I read worked for me.  I did, however, find a solution, through experimentation:

After setting up the envelope properties in my word processor's envelope printer function (in my case, paper size was #10 envelope, centered the long way, fed with the stamp on the underside on the trailing end), I also checked the page setup properties and found that the paper size had not automatically changed from letter size to envelope size, as I would have expected it to do, so I did it manually. (The orientation had automatically changed to landscape , however, so I didn't have to change that.)  But that still didn't help.  Then I went into the HP Printer Assistant app, to "customize your printer", and noticed that under the "General" tab the "paper available" field still showed as "letter" instead of envelope.  You're not allowed to change it there, but I clicked on the "device settings" tab, which shows the current settings in an outline format with dropdowns that allow selections.  I changed the main tray's paper size to #10 envelope, and when I went back to the "general" tab, it now showed the correct size.  I then tried printing the envelope, and was finally able to do it without getting the "paper mismatch" error.

I don't pretend to understand any of this, but I find that since then, whenever I do any  printing, the paper size remains at "#10 envelope" in the "customize your printer" settings, and yet I can print either letter-size documents or envelopes, and don't get any mismatch errors. (Admittedly I haven't yet tried rebooting my computer to verify that the setting will remain like that permanently.)

NOTE:  You can also get to the printer settings outline through Windows settings/devices/printers/(click on your printer and click "manage")/printer properties/device settings .

I hope this helps someone else.  Prior to this, I'd been taping envelopes to letter-size paper to get the job done, and I'm happy I no longer have to do that.