It sounds like you are not using Internet Explorer as your default browser then or may not have set the mailto protocol in Windows to use Outlook.
How can I get mailto links to open with Outlook again? I've already made sure that Outlook has been set as my default mail client in Windows, but mailto links still bring me to Gmail. Now, when I click on a mailto link, it brings up the Gmail webpage while I don't even have a Gmail account. When clicking on a mailto link, Outlook used to get opened and I could write my email.
