Tap here to go to the mobile version of the site.
Your Firefox is out of date and may contain a security risk! Upgrade Firefox

Support Forum

Don't like the new pdf.js viewer. How can I disable it and restore Acrobat Reader as my preferred plugin?


I really don't like the look-and-feel of the new pdf.js viewer. On my machine (6 yr old HP running Windows XP with sp 3) it displays slower than Acrobat Reader did, and I was perfectly happy with Acrobat Reader plugin. Frankly I want to disable pdf.js, but haven't been able to figure a way to do it. It doesn't display anywhere I could find on Add-ons Manager. I don't want to be compelled to use a feature that seems to be a performance detriment, at least for me. Mozilla, please rethink this!

Chosen solution

You can set the pdfjs.disabled pref to true on the about:config page to disable the build-in PDF viewer and use the Adobe Reader instead.

See also:

Read this answer in context 21

Additional System Details

Installed Plug-ins

  • Google Update
  • Adobe PDF Plug-In For Firefox and Netscape 11.0.02
  • Next Generation Java Plug-in 10.13.2 for Mozilla browsers
  • NPRuntime Script Plug-in Library for Java(TM) Deploy
  • Google Talk Plugin Video Accelerator version:
  • Version
  • Shockwave Flash 11.5 r502
  • RealPlayer(tm) LiveConnect-Enabled Plug-In
  • RealPlayer Download Plugin
  • VLC media player Web Plugin 2.0.2
  • RealNetworks(tm) RealDownloader Chrome Background Extension Plug-In
  • RealNetworks(tm) RealDownloader PepperFlashVideoShim Plug-In
  • RealNetworks(tm) RealDownloader HTML5VideoShim Plug-In
  • RealDownloader Plugin
  • Garmin Communicator Plug-In
  • The QuickTime Plugin allows you to view a wide variety of multimedia content in Web pages. For more information, visit the QuickTime Web site.
  • RealNetworks(tm) RealPlayer Chrome Background Extension Plug-In
  • RealPlayer(tm) HTML5VideoShim Plug-In
  • Adobe Shockwave for Director Netscape plug-in, version
  • 5.1.10411.0
  • iTunes Detector Plug-in
  • DivX Plus Web Player version
  • AmazonMP3DownloaderPlugin 1.0.15
  • DivX VOD Helper Plug-in
  • npmnqmp 989898989877
  • Garmin Communicator Plug-In
  • getplusplusadobe16248
  • 1.9.0042.0
  • Windows Presentation Foundation (WPF) plug-in for Mozilla browsers
  • DRM Netscape Network Object
  • Npdsplay dll
  • DRM Store Netscape Plugin
  • Office Plugin for Netscape Navigator
  • Windows Multimedia Services DRM Store Plug-In


  • User Agent: Mozilla/5.0 (Windows NT 5.1; rv:19.0) Gecko/20100101 Firefox/19.0

More Information

frogguy 0 solutions 2 answers

Edster, I'm not sure Mozilla reads the feedback messages anymore than they monitor these support forums. LOL

robbyrob 0 solutions 1 answers

The following worked for me with version 20.0.1 (the latest, I believe) under Windows XP Professional 32-bit:

  1. In about:config, set pdfjs.disabled to true, set pdfjs.firstRun to false.
  2. If you have a preference called plugin.disable_full_page_plugin_for_types that has the value "application/pdf", right-click on it and select "reset". That will set its value to null.
  3. Restart Firefox.

That being said, I wholeheartedly agree with the other commenters that the "pdfjs" plugin is slow, has less functionality, and is buggy. There are many PDFs that it won't display correctly or at all. It also caused Firefox to crash on me today. The steps necessary to use Adobe's plugin are rather convoluted and poorly documented (if at all). For an organization and a software product that claim to be committed to user-friendliness, I think this whole "pdfjs" affair reflects very badly on Mozilla and Firefox.

Modified by robbyrob

mdw302 0 solutions 1 answers

I had this problem and corrected it on my computer. But there still is a huge issue here. I work for a university Cooperative Extension service, and we post a great deal of PDFs on our website. I have several examples where important information is completely omitted in the PDF with this viewer. Now, the public will see the nice pale yellow banner saying "This PDF document might not be displayed correctly" and then offers a different viewer to use on the right. That is not strong enough. Might? I am not confident that the general public will follow through. Why? If the one comes up and looks fine, why bother? My example shows a list of workshops, their times and cost. Everything looks in order. I do not see the "Full" and "This session has been cancelled" that we uploaded to our website and that displays correctly when I view the PDF with IE, Chrome, Safari or Opera. People aren't going to click on another viewer if they don't think anything is wrong. The average person is not going to bother. The warning is to blah and not strong enough! I have fixed it for my own viewing, but will thousands of others do that? I think this is a huge problem and puts into question the integrity of PDFs viewed in Firefox! We are going to have to put disclaimers now on all of our PDFs saying "Best viewed using Internet Explorer, Chrome, Opera, or Safari" Not happy about this new feature at all!

Modified by mdw302

VikkiO 0 solutions 4 answers

Exactly, how many general users are going to go the extra mile to figure this out? I doubt very many. This is totally ridiculous.