Yes it brings up another window showing the print page.

I'll check for the empty spaces next time I print an email.

Please note that your email to me printed just fine, nothing missing. So I tried to print a message from PayPal, the print dialog was missing the text, and of course the missing text was missing on the printed pages. When I try to print this same email with Microsoft Edge, it prints correctly with no missing text.

Some other emails I receive, when I try to print them with Firefox, the print dialog is not missing the text and they print correctly.

I uploaded a New York Times email screenshot and the Firefox print dialog screenshot. This shows what I am seeing.

I also have an email from "Electronic Goldmine" that is quite long. When I try to print that email in Firefox, the print dialog shows it will be 13 pages. When I scroll thru the pages in the print dialog they are almost all blank except for the first and last pages. (note also that in Microsoft Edge it looks like 13 pages but they didn't put the pictures of the products into the pages! So looks like Edge has some bugs too.)

RE: Unable to print viewable Yahoo emails on Firefox over Windows 10. After spending a considerable amount of time on this, I finally found the solution. You need to switch back to Yahoo Basic Mail. Otherwise, when you use print preview, it will only show the headings and cut off sections of what you are trying to print. INSTRUCTIONS: 1. Go into Yahoo email. 2. Go into "Settings", all the way to the right side of the screen. 3. From there, scroll down and then click on "More Settings". 4. On the left side of that screen, you will see "Switch to basic Mail". Switch back. That should solve the problem.

I have tried all solutions I have found so far. This only seems to happen when I am trying to print Yahoo mail in Firefox. No problem in other browsers or with other email services in Firefox. Seems to be specific to Yahoo and Firefox used together.