FAQ | Frequently Asked Questions

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UC Davis Geology Department Computing Support Team

Q: How do I view PDF files with Firefox 12 through 18?
A: With the release of Firefox 19 on March 11, 2013, Firefox now has a built-in PDF viewer. Upgrading to Firefox 19 or later may resolve your issue.

For versions of Firefox previous to version 19:

Recent security upgrades regarding the Adobe Reader browser plug-in have resulted in Firefox and other browsers being incompatible with popular PDF-viewer plug-ins.

Adobe Acrobat Reader plugin blocked on Mac OS X from the Mozilla Add-Ons blog, May 4, 2012

The Adobe Acrobat Reader plugin is currently causing problems for most Mac OS X users who have it installed. In the majority of cases, the plugin shows a blank page when a user clicks on a link to a PDF file. There are also reports of crashes when using the plugin in 32 bit mode. For this reason we have decided to add the plugin to the blocklist.

Mac OS X users who have this plugin installed will be prompted to disable it in the next 24 hours. You will have the option to keep it enabled, and even if you disable it when prompted, you will have the option to re-enable it in the Add-ons Manager. We are not blocking the Adobe Flash plugin, only the Adobe Acrobat NPAPI plugin.

We are currently working with Adobe so that a fixed version is released soon. We will post an update on this blog once that happens.


Note: You may be able to download a newer version of the PDF Viewer add-on/plug-in for Firefox from https://addons.mozilla.org/en-US/firefox/addon/pdfjs/.

Another way to re-enable PDF viewing is to reconfigure Firefox to change the application that Firefox triggers when a PDF document is downloaded.

In FirefoxPreferences select the Applications section.
Screenshot: firefox preferences pdf

Find the setting for Portable Document Format or PDF. Change the Action to Use Preview (default).

If you are using Windows, set the Action to Adobe Reader or some other appropriate application.

If you don't have an application setting for Portable Document Format or PDF documents then you probably see the Always Ask window.
Screenshot: Firefox PDF Always Ask window
In this window you can specify what Firefox should do with PDF files.

If you check the Do this automatically… box, then Firefox should create a Content Type entry in the Applications preferences.

On a related note…

Q: How do I save a PDF file in Safari?
A: In Safari (v 5.1.5) when viewing a PDF document if you mouse over the lower portion of the page a dark rectangle will appear. It contains four icons.

Clicking the rightmost icon will download the PDF to your designated Downloads folder.

Clicking the icon just to the left of that one, the icon showing pages and a loupe, will open the PDF document in Preview.

The two left icons are magnifying glasses with "-" and "+" in the magnifier. Use these two icons to zoom in and out.
Screenshot: Safari save PDF