Some user have come across a bug in the Visual Studio Tools for Office runtime that means that an AddIn is disabled when "Outlook without a UI" is used, sometimes referred to as headless mode!
What does this mean? Well, if you are running ActiveSync or you regularly right click items in explorer in order to 'Send To -> Mail Recipient' you may have found that occasionally when you load Outlook, the spamREF toolbar is missing from the screen and needs to be re-enabled by the 'Options -> Other -> Advanced Options -> COM Add-Ins' route. Pretty annoying if you like your right click and/or ActiveSync!
The good news is the bug has been fixed so you never need to worry again, apparently! Download the version from here:-