This site will have limited functionality while we undergo maintenance to improve your experience. If an article doesn't solve your issue and you want to ask a question, we have our support community waiting to help you at @FirefoxSupport on Twitter and/r/firefox on Reddit.

Search Support

Avoid support scams. We will never ask you to call or text a phone number or share personal information. Please report suspicious activity using the “Report Abuse” option.

Learn More

Opening a pdf in Firefox causes endless new tabs to appear in Firefox

  • 3 replies
  • 4 have this problem
  • 2 views
  • Last reply by FredMcD

more options

When I attempted to open a pdf file using Firefox's 'PDF Viewer', lots of blank new tabs suddenly appear and will not stop appearing until I choose to open the pdf file with a different program (eg Microsoft Edge). This occurs in ALL pdf files.

Setup: Windows 10 Pro, Build 1607 Firefox, version 48.0.2 (latest)

When I attempted to open a pdf file using Firefox's 'PDF Viewer', lots of blank new tabs suddenly appear and will not stop appearing until I choose to open the pdf file with a different program (eg Microsoft Edge). This occurs in ALL pdf files. Setup: Windows 10 Pro, Build 1607 Firefox, version 48.0.2 (latest)

All Replies (3)

more options

Deleting the mimeTypes.rdf will reset all download actions to the default settings.

Type about:support in the address bar and press enter.

Under the page logo on the left side, you will see Application Basics. Under this find Profile Folder. To its right press the button Show Folder. This will open your file browser to the current Firefox profile. Now Close Firefox.

Locate the above file. Then rename or delete it. Restart Firefox.

more options

I've tried both renaming and deleting the file, and also reinstalling Firefox, but none of those have worked.

more options