How to Fix Problems Viewing PDFs using Firefox (newer versions 19+)

This page discusses how to fix the display/printing of PDFs when the fonts appear irregular.

Do your PDFs look like this?

PDF using internal Firefox viewer

Instead of this?

PDF using Adobe Acrobat Plug-in for Firefox

If so, follow the steps below to fix the problem:

Beginning with version 19, Firefox added its own PDF viewer, which doesn't always render some fonts correctly.  More than likely, your Firefox browser is using the built-in PDF viewer instead of the Adobe Reader (aka Adobe Acrobat) plugin to display PDF files.  To switch from the built-in viewer to the Adobe Acrobat plugin:

1. Make sure the latest version of the free Adobe Reader is installed on your computer. Here are a few ways to check:
2. If you don't have Adobe Reader, click this icon get Adobe Reader to download it and install it.

3. After verifying that Adobe Reader is installed on your computer:
  1. From the Firefox main menu, select Tools > Add-ons and click Plugins on the left.
  2. You should see Adobe Acrobat in the list of plugins and to its right the pull-down tab should say "Always Activate".  If not change it to "Always Activate".
  3. Close the Add-ons Manager.
4.  From the Firefox main menu, select Tools > Options and click the Applications Icon (in the row of icons across the top).
  1. You should see something like this: Options Applications

  2. In the Search field, type "pdf" and you will see: Options Applications type pdf

  3. Under Action, select "Use Adobe Acrobat (in Firefox)": Options Applications select Adobe Acrobat
  4. Click OK.
That's it!

Now go back to view your PDFs in Firefox.  If open, close them and then re-open.  Your fonts will look and print correctly.