Hello,

In order to change the default reader for PDF files (to not open PDF files with Firefox's internal PDF reader), follow these steps:

1. Click the menu button and click Options (Preferences for Linux and Mac).
2. In the Options (Preferences for Linux and Mac) tab (window for previous than 38.0 firefox version), select the Applications panel.
3. In the Search field, type PDF. You should find Portable Document Format (PDF).
4. On the right hand side you should find an Action column. Use that to select your favorite PDF reader. In order to view PDF files in Firefox, choose Preview in Firefox.

Did this fix your problems? Please report back to us!

Thank you.

You seem to have misunderstood me. I want pdf's to preview in Firefox 43.

Sorry about that, sometimes resetting the default will do that, but I think you need the pdf.js to preview in Firefox.

But starting over in order to fix it if its not doing what it has asked:

• Reset Firefox preferences to troubleshoot and fix problems

Before I try resetting preferences, let me describe my problem more precisely. I can preview any number of PDF's from websites such as for instance Dell manuals, but I cannot view the pdfs of tax maps from my town's website. The town clerk says the problem is my computer, but she would say that wouldn't she? What do you think the problem is?

What happens if you try to open such a PDF from your town's website?

Note that the built-in PDF Viewer only works with files send by the server as application/pdf.

Hi cor-el, good to talk to you again. When I try to open a pdf from my town's website, I get a buffering circle for a second or so then just a white page.

I do not understand what you mean by "application/pdf" The website lists about thirty different tax maps as name.PDF The clerk says they open perfectly on her computer.

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

Sure. You mean to the tax maps on the website. Here you go cor-el.

http://www.wiscasset.org/taxmaps/

Those PDF links work for me and open the PDF Viewer, so there is nothing wrong with the files and the internet server. It takes a few seconds for Firefox to draw the map.

See also:

• https://support.mozilla.org/kb/view-pdf-files-firefox-without-downloading-them
• https://support.mozilla.org/kb/disable-built-pdf-viewer-and-use-another-viewer

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

• Switch to the DEFAULT theme: Firefox 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

Thank you cor-el,

In safe mode the pdf tax maps appeared. Progress! Great.

So I unchecked hardware acceleration, and voila, in regular mode the tax map pdf appeared.

My question is what is hardware acceleration, and what do I lose with out it? Should I leave hardware acceleration unchecked or not? I may not need to look at these tax maps again.

My question is what is hardware acceleration, and what do I lose with out it? Should I leave hardware acceleration unchecked or not? I may not need to look at these tax maps again. Is it likely that hardware acceleration affects more than this one website's pdf's?

Hardware acceleration means that Firefox uses the GPU (processor on the graphics display card) instead of the CPU to do some operations. You may not notice any effect on the performance of Firefox if hardware acceleration is disabled.

• https://hacks.mozilla.org/2010/09/hardware-acceleration/

Thank you cor-el for all your help.