Issues have been previously linked to the McAfee Site Advisor extension. Try to disable it and see if the problem persists.

http://service.mcafee.com/faqdocument.aspx?id=TS100162 How to uninstall SiteAdvisor

To disable it: Type "about:addons" in the Location bar Find the extension and click on its "Disable" button

Without using your real address, please post the link you are using.

Thank you for the help - but I have already uninstalled McAfee from my computer. Is it possible that this add - on - is still there but I cannot find it.

thank you for your help.

Fred was looking at the information on the right side of your post: Question Details > More System Details. On the Add-ons page, there are separate categories for Plugins and Extensions (you can click the button on the left to select).

The error code sounds like a Windows error. Does that appear after you click an email link, or while trying to make a change in the Options page, or while adding the handler to Firefox?

Could you walk me through the steps you are following to set up your email link?

These are the steps I am following to set up the email link. I click File - and and Email Link. What then appears is a box with an envelope which opens to request that I input an email account to connect to. I then input all of my yahoo mail account info - and then it says it does not recognize this account and I cannot go any further. Then I tried to input the information for my gmail account. It recognizes the account but when I click on the last prompt to connect it - the error message comes up. The error message comes up also when I try to manually create my yahoo account. The same thing happened when I tried to input my microsoft account.

When I choose File > Email Link, I get a list of available email clients, some of which come with Firefox, some of which were found on the system, and some of which I probably added at some point. I am attaching a copy of what I see.

Do you get that dialog? If so, what are you selecting there?

If you do not get that dialog, let's reset what you have now so you have a choice. This article has the steps to access the Applications panel of the Options page, and you can select "Always Ask"

And then... what do you select?

Also, dumb question maybe, but does it help to log into Yahoo Mail BEFORE using Email Link so that you don't have to do that step as part of the process?