See:

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

I followed these instructions prior to posting my question. It did not solve the p[problem.

What did you do?

Did you check the Mailto setting in Tools > Options > Applications?

Did you try to delete the file mimeTypes.rdf in the Firefox Profile Folder if the above didn't help?

• http://kb.mozillazine.org/Profile_folder_-_Firefox
• Help > Troubleshooting Information > Profile Directory: Open Containing Folder

The mailto option is set at always ask. There is no option to use Firefox as the email manager. I deleted the mimetypes folder.

You can also check some prefs on the about:config page

You can open the about:config page via the location bar and do a search for mailto via the Filter at the top of the about:config page.
You can reset all mailto prefs that appear bold (user set) via the right-click context menu to their default values.

To open the about:config page, type about:config in the location (address) bar and press the "Enter" key, just like you type the url of a website to open a website.
If you see a warning then you can confirm that you want to access that page.

• Use the Filter bar at to top of the about:config page to locate a preference more easily.
• Preferences that have been modified show as bold(user set).
• Preferences can be reset to the default or changed via the right-click context menu.

I opened the config folder and didn't find any that had been user set. Interestingly there is no preference to use Firefox mail manager when using mailto. At this point I have opened a gmail acount and use the mailto option through gmail. Then I have all my gmail forwarded to my comcast. When I did this i could not check the "make this default" box. If I did, the same problem occurred.