You get this problem if you select the Firefox program to handle a file when you get an "Open With" dialog.

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

You can try rename (or delete) the mimeTypes.rdf file in the Firefox profile folder to reset all file actions.

• http://kb.mozillazine.org/mimeTypes.rdf
• http://kb.mozillazine.org/File_types_and_download_actions#Resetting_download_actions

You can use this button to go to the Firefox profile folder:

• Help > Troubleshooting Information > Profile Directory: Show Folder (Linux: Open Directory; Mac: Show in Finder)

No "open with" dialog. In the past, I would click on the link and it would immediately open my default email client. In this case, AOL from the webpage, not stand alone software.

You can check the network.protocol-handler.external.mailto prefs on the about:config page.

If network.protocol-handler.external.mailto prefs are user set (bold) then right-click and Reset them to the default value.

You can open the about:config page via the location bar.

Not bold.

status = default, type = boolean, value = true

Still nothing, here. Should I just uninstall Firefox and reinstall it or won't that help? Can I save all my bookmarks someplace?

FWIW, I'm running into other weird behaviors like clicking links that don't do anything at all and email that won't open.

We have a support article for this https://support.mozilla.org/en-US/kb/Hyperlinks-in-Messages-Not-Working#w_firefox

Try resetting the default in Firefox as suggested in the article. The tools menu is ALT+T

I would also suggest you use a product like malware bytes to scan your system, the process of opening loads of tabs like that is often indicative of a malware infection. If you are using a Microsoft security product, scan your system with something else. Their products are only So-So when in comes to virus and malware.

It may also be that malware has reset your default browser as it is easy to do and gives the malware author a known platform to play their tricks on.

Did you delete the mimeTypes.rdf file?

You can use this button to go to the Firefox profile folder:

• Help > Troubleshooting Information > Profile Directory: Show Folder (Linux: Open Directory; Mac: Show in Finder)

Matt, I double checked and Firefox is still the default browser. A Malwarebytes scan did not clear up the problem.

Cor-el, I'll try to remove the mimeTypes.rdf file

Cor-el, I removed the mimeTypes.rdf file and restarted the computer. The problem still persists.

And it turns out that the "Navigation cancelled" error is on every tab except for the first one.

The first IE tab says: Could not perform this operation because the default mail client is not properly installed.

When I close that tab, the numerous other tabs open rapidly.

I've tried to figure out how to re-set the default mail client but I cannot find the option.

I have tried the following steps... Tools, Options, Applications, emailto.

emailto shows the action: use handemailto (default).

When I click on that tab, it lists Always ask, Use handemailto (default), Use Yahoo! mail, Use Gmail, Use other.

Application details

Use AOL is not one of the options and clicking on Use other brings up a page with mailto 'undefined'. There's a blank area labeled "send this item to" but I cannot fill in the blank with mail.aol.com.

Clicking on Application details lists Yahoo! mail and GMail and I can remove either/or both of them on this page.

I feel like I should be able to add AOL mail on the Use other page but I'm unable to. Also, I have always used AOL so the whole problem is puzzling.

Still no luck on this end...

i have problem too with this ask. still follow this answer

[link(s) removed by Moderator]

Anyone? Anyone? Bueller? Bueller?

Do a malware check with several malware scanning programs on the Windows computer.
Please scan with all programs because each program detects different malware.
All these programs have free versions.

Make sure that you update each program to get the latest version of their databases before doing a scan.

• Malwarebytes' Anti-Malware:
  http://www.malwarebytes.org/mbam.php
• AdwCleaner:
  http://www.bleepingcomputer.com/download/adwcleaner/
  http://www.softpedia.com/get/Antivirus/Removal-Tools/AdwCleaner.shtml
• SuperAntispyware:
  http://www.superantispyware.com/
• Microsoft Safety Scanner:
  http://www.microsoft.com/security/scanner/en-us/default.aspx
• Windows Defender: Home Page:
  http://www.microsoft.com/windows/products/winfamily/defender/default.mspx
• Spybot Search & Destroy:
  http://www.safer-networking.org/en/index.html
• Kasperky Free Security Scan:
  http://www.kaspersky.com/security-scan

You can also do a check for a rootkit infection with TDSSKiller.

• Anti-rootkit utility TDSSKiller:
  http://support.kaspersky.com/5350?el=88446

See also:

• "Spyware on Windows": http://kb.mozillazine.org/Popups_not_blocked

After receiving this last recommendation, I walked away from it. I didn't have the time available to go through all those steps. It was easier to just not use Firefox when logging onto Craigslist.

So here we are, two weeks later. I still haven't done anything about it but the problem is now gone. Apparently Mozilla fixed whatever the problem was or perhaps it was a Window issue that was fixed with a recent update.

Whatever the case, the mystery was never solved but it no longer exists.