hello nonditgrig,

please try the following:

Click the Menu and choose Options. Select the Applications panel on the left. Check "Preview in Firefox" is set for "Portable Document Format (PDF)" -- if not, change it to this. See View PDF files using Firefox’s built-in viewer for a screenshot of what this page looks like.

If it is already set to that and it still won't load with the built-in viewer, please let us know.

when resolved your problem mark solution.

Thanks!

I invited nonditgrig to a screen sharing session, and I'll give an update here once we are done.