There are still bugs in the built-in PDF Viewer that cause issues with some PDF files.

Can you post a link to a publicly accessible page (i.e. no authentication or signing on required) where you encounter issues?

Most of the pdf files that used to open just fine have started having issues now.

But for test purpose you can try this one: http://www.pdf995.com/samples/pdf.pdf

That PDF file seems to be working fine here.

When did it stop working for you?

Do you see any error or security messages in the Web Console (3-bar Menu button or Tools > Web Developer)?

• https://developer.mozilla.org/Tools/Web_Console

All of the pdf files stopped displaying fully all of a sudden 2 days ago.

Should I look for errors on the web console after I load one of the pdf pages in question?

This is what the web cosole says when I am on the test pdf page

PDF 092267edd57c0545aad583afa8502b94 [1.3 GNU Ghostscript 7.05 / Pdf995] (PDF.js: 1.1.551)

What images or graphics are missing in that PFD file?

Can you attach a screenshot?

• http://en.wikipedia.org/wiki/Screenshot
• https://support.mozilla.org/kb/how-do-i-create-screenshot-my-problem

• Use a compressed image type like PNG or JPG to save the screenshot
• Make sure that you do not exceed the maximum size of 1 MB

Page 1 of that file is completely blank. Page two just has the header image. I don't think it matters if I post the image of a blank paper.

I've seen another question about a problem with the built-in PDF Viewer on Mac in Firefox 44, so I'm not sure if this is a Mac specific issue.

• [/questions/1110162] But for realz, now, how can I view PDFs in Firefox (native viewer does NOT work even if "activated")?

Start Firefox in Safe Mode to check if one of the extensions (3-bar Menu button/Tools > Add-ons > Extensions) or if hardware acceleration is causing the problem.

• Switch to the DEFAULT theme: 3-bar Menu button/Tools > Add-ons > Appearance
• Do NOT click the Reset button on the Safe Mode start window

• https://support.mozilla.org/kb/Safe+Mode
• https://support.mozilla.org/kb/Troubleshooting+extensions+and+themes

Try to create a new profile as a quick test to check if your current profile is causing the problem.

See "Creating a profile":

• https://support.mozilla.org/kb/profile-manager-create-and-remove-firefox-profiles
• http://kb.mozillazine.org/Standard_diagnostic_-_Firefox#Profile_issues

If the new profile works then you can transfer files from a previously used profile to the new profile, but be cautious not to copy corrupted files to avoid carrying over problems.

• http://kb.mozillazine.org/Transferring_data_to_a_new_profile_-_Firefox

I just refreshed firefox and it solved my problem.

https://support.mozilla.org/en-US/kb/refresh-firefox-reset-add-ons-and-settings

Thank you for all your help.