by Howard B. Richman
Normally, in Firefox, there is a bundled viewer for pdf files. This allows you to quickly view the pdf without having to download it. Recently (for me it was March 2017, but it seems to be different for other people) this stopped working properly when attempting to PRINT. Screen view was fine but when you would print, the tops of letters or images would be cut off. I did spend quite a bit of time on this. At first, I thought it was a printer problem. Then I figured out how to make Adobe Acrobat Reader as the default pdf viewer, but I was not happy with that because it requires that each pdf that you want to view be DOWNLOADED and that takes extra time. In my case, I’m printing multiple invoices from my Amazon store each day and the added time delay to download and start the Adobe Acrobat program (which is very slow on startup) was quite a drag.
Switch to a Different PDF Viewer
Click the Menu Button 
in the upper right hand corner.
Options > Applications > Scroll to “Portable Document Format”
Choose the program you want to use to view PDF Files.
Try Updating the Built-In PDF Viewer
My first thought is that maybe I need to update my version of Firefox. It turned out that I DID have the most recent update and there was nothing that I could do. But it does seem that the built-in viewer that is bundled with my “most recent” version of Firefox WAS NOT THE MOST RECENT VIEWER!!!!! AH HA!!! I found a link where you can download JUST THE VIEWER:
https://mozilla.github.io/pdf.js/
Install this viewer and then it probably still won’t work unless you do this: Follow the directions in the above section to “Switch to a Different PDF Viewer.” (For example, temporarily switch to Adobe Acrobat Reader.) Then close down Firefox and restart Firefox. THEN get back to that window where you can switch PDF viewers and choose “Preview in Firefox.”
That should work. I’m using Windows 10. I’m not sure if this works for MAC. Please let me know if you have success.
