make sure you are not running the pdf.js reader

• View PDF files in Firefox or choose another viewer
• PDF files are blank or cause an error message on Mac
• Use Adobe Reader to view PDF files in Firefox

Make sure you read all articles before procedding.

The Adobe Reader plugin may not be working properly on Mac.

• https://support.mozilla.org/kb/pdf-files-are-blank-and-cant-be-downloaded-mac
• https://support.mozilla.org/kb/Opening+PDF+files+within+Firefox

Disable the Adobe Reader plugin in Firefox (Tools > Add-ons > Plugins) and use the external Adobe Reader application or Preview application instead.

PDF files may be found under entries like Portable document or Adobe PDF document or Adobe Acrobat Document.

• Firefox > Preferences > Applications > Adobe PDF document : Use Adobe Reader

• https://support.mozilla.org/kb/change-firefox-behavior-when-open-file

Make sure you have cookies enabled.

Do you have any other PDF viewers installed on your computer? If you do, try uninstalling it because sometimes it can confuse Firefox.

Make sure your anti-virus program is set to allow Adobe Reader internet connection.

Make sure the Adobe Reader plugin and program is up-to-date.

(for the record)

This is a known issue with the Adobe Reader plugin on Mac OS:

• Bug 811085 - Can't use Adobe Reader for PDF files

Read the above bug for details (please don't comment in the bug report).

To work around this,

1. disable the Adobe Reader plugin in the Firefox Tools -> Add-ons -> Plugins list
2. choose another action for Portable Document Format (PDF) content types in the Firefox Preferences -> Applications list, such as "Preview in Firefox" to use the built-in PDF viewer, "Preview" application or the Adobe Reader application itself

Related articles:

• PDF files are blank or cause an error message on Mac
• View PDF files in Firefox or choose another viewer
• View PDF files in Firefox or choose another viewer