mailto client is missing
I tried using the email link in Firefox 33. It opened an "open with" window. Checked for support online. Followed the instructions to configure the mailto client in the applications. When I searched for mailto it was not there. I reset Firefox. Turned off the computer for a while. When I started Firefox up again checked if mailto was in the applications list. It was there. I also noticed in my plugins H264 was there. I know it is part of the developers software now, but I do not want it. So I removed it. Then mailto was gone again. I reset Firefox again to see if mailto came back. It was still not there. Tried restarting the computer. Still not there. I have added some plugins. They are Better Privacy, Ads no more, Smart Ads Blocker, and Yahoo Mail Hide Ad Panel. Is it the plugins, or something else that is making this happen? Please let me know.
You can try to rename (or delete) the mimeTypes.rdf file in the Firefox profile folder to reset all file actions.
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.