I must have clicked something in error on my Win 8 PC as when I open one of our SharePoint 2010 sites and select a file, right clicked and selected Send To > Email Link instead of an Outlook email opening my PC tries to open Chrome.
A bit of quick digging showed the issue was that the file association for mailto: was wrong. You can check this setting in IE > Internet Options > Programs > Internet Programs > set Programs (button)
Once I changed this to Outlook I got the behaviour I expected