Firefox may repeatedly open new, empty tabs or windows after you click on a link, forcing you to close Firefox. The same untitled tabs or blank windows may open the next time you start Firefox if the previous session is restored.

This usually happens because you chose Firefox as the program to always use for a particular action, such as opening a certain type of file or launching an application to send mail.

Start a new Firefox session

You may be forced to close Firefox if it is repeatedly opening multiple tabs or windows. Firefox includes a Session Restore feature that can restore your windows and tabs from the previous session after a crash or unexpected close.

The same multiple tabs or windows may start opening when you next start Firefox, forcing you to close Firefox again. If you see a Restore Session ( "Well, this is embarrassing.""Sorry. We're having trouble getting your pages back.") page when you restart Firefox, click the CloseStart New Session button to start a new session and then follow the instructions given below to fix the problem.

Change the action for a content type

You may be able to fix the problem by finding the content type that is set to use Firefox and then changing the action, using these steps:

1. Click the menu button and choose Options.Preferences.
2. Select the Applications panel.In the General panel, go to the Applications section.
3. If you know which item in the Content Type column is causing the problem, select it. Otherwise, in the Search box, type Use Firefox. The list will display only items that are set to "Use Firefox".

   

4. For each problematic content type, select a new action from the menu in the Action column. If you're not sure which action to pick, choose Always ask.
5. Close the about:preferences page. Any changes you've made will automatically be saved.

For general information on content types, see Change what Firefox does when you click on or download a file.

Reset actions for all content types

If the preceding steps didn't fix the problem, or if you can't find the problematic item in the Applications list, you will have to reset the actions for all content types by manually deleting the file that stores these settings.

1. Open your profile folder:

   Click the menu button , click help Click the menu button , click Help and select Troubleshooting Information. The Troubleshooting Information tab will open.

   • Under the Application Basics section, click on Show FolderOpen FolderShow in FinderOpen Directory. A window will open that contains your profile folder.Your profile folder will open.
   Note: If you are unable to open or use Firefox, follow the instructions in Finding your profile without opening Firefox.

2. Close Firefox.

   Click the menu button and then click ExitQuit .

   Click the Firefox menu , then click Exit. Click the Firefox menu at the top of the screen, then click Quit Firefox.Click the Firefox menu , then click Quit.

3. Delete the file named mimeTypes.rdfhandlers.json.
4. Restart Firefox.