You get that problem if you select the Firefox program to handle a file if you get an "open with" dialog.

• https://support.mozilla.com/kb/Firefox+keeps+opening+many+tabs+or+windows

Could you explain this further? I'm simply clicking on a live link and having a series of blank pages open. I don't know where this "open with" dialog box is.

That is the dialog that you get when you download and save a file, but you also get it when Firefox encounters a file that isn't send as text/html or text/plain or another recognized MIME type.
If you choose Firefox as the application to handle that file then you end up with countless tabs opening, like happened in your case.
You will have to remove that file action.

See : Tools > Options > Applications

• http://kb.mozillazine.org/File_types_and_download_actions
• https://support.mozilla.com/kb/Managing+file+types

Hi -- Thanks for trying to help. But I'm not getting a dialog about opening a file with Firefox as the application. I'm just clicking on a link within a web page. This makes an infinite number of new blank windows appear, which only stops when I quit Firefox. I have used previous versions of Firefox and have never had this problem before.

Try the solution from this thread for the pencil icon:

• [/questions/883573]
• Delete the Firefox icon from the dock.
• Create a new icon by dragging the Firefox application to the dock.

You may have gotten such a pop-up in the past and ticked the box to always use that choice.

You will either have to remove that action in "Firefox > Preferences > Applications" or delete the file mimeTypes.rdf in the Firefox profile folder to reset all file actions if you can't find it in "Firefox > Preferences > Applications".

• Help > Troubleshooting Information > Profile Directory: Open Containing Folder

• http://kb.mozillazine.org/File_types_and_download_actions