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firefox can not open pdf, can not find pdf in the Content Type under Preferences --> Applications

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I have Acrobat Reader DC version installed on MacBook Pro, but, everytime firefox tried to open pdf file, it asks me to install Adobe Acrbat NPAPI plug-in, and when I allow/remember, it just gives me blank screen. All the search results suggest that I fixed it by going to the Firefox Preferences, Application tab, search PDF, or Portable Document, for the Content Type, and enable the Adobe Acrobat NPAPI Plug-in. BUT, my search for PDF returns nothing. All I have is Adobe Acrbat FDF document, What should I do to fix this problem in this case?

I have Acrobat Reader DC version installed on MacBook Pro, but, everytime firefox tried to open pdf file, it asks me to install Adobe Acrbat NPAPI plug-in, and when I allow/remember, it just gives me blank screen. All the search results suggest that I fixed it by going to the Firefox Preferences, Application tab, search PDF, or Portable Document, for the Content Type, and enable the Adobe Acrobat NPAPI Plug-in. BUT, my search for PDF returns nothing. All I have is Adobe Acrbat FDF document, What should I do to fix this problem in this case?

Chosen solution

Hello there,

Type about:preferences#applications<Enter> in the address bar. What is the information for those type files?

Did you want to show the file in Firefox, or another viewer?

For more details please view this topic: https://support.mozilla.org/en-US/questions/1045938

Hope this helps

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Seçilmiş Həll

Hello there,

Type about:preferences#applications<Enter> in the address bar. What is the information for those type files?

Did you want to show the file in Firefox, or another viewer?

For more details please view this topic: https://support.mozilla.org/en-US/questions/1045938

Hope this helps

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When you enter PDF in the search box above the list, Firefox should show just Portable Document Format. If that's missing, the file that stores the application handling preferences might have become corrupted. Since the file is difficult to edit, we generally suggest renaming it and letting Firefox start a new one. Here's how:

Open your current Firefox settings (AKA Firefox profile) folder using either

  • "3-bar" menu button > "?" button > Troubleshooting Information
  • (menu bar) Help > Troubleshooting Information
  • type or paste about:support in the address bar and press Enter/Return

In the first table on the page, click the "Show in Finder" button. This should launch a new window listing various files and folders.

Leaving that window open, switch back to Firefox and Exit, either:

  • "3-bar" menu button > "power" button
  • (menu bar) File > Exit or on Mac it might be Firefox > Quit

Pause while Firefox finishes its cleanup, then rename mimeTypes.rdf to something like mimeTypes.old (in case you need to recover it later).

Start Firefox back up again, and return to the Application preferences to select your preferred viewer. Is Portable Document Format listed?

Note: if you previously customized the setting for email links, you'll need to fix that one, too. See: Change the program used to open email links.

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I enter about:preferences#applications <Enter> in the address bar, I searched for PDF, or Portable Document, neither of them returned anything. The only one I have is Adobe Acrobat FDF document. OK, then, I see "Preview.app Document", changed from "Always ask" to "Use Adobe Acrobat Reader", that fixed the problem.

Thanks.