I've built a VTSO add-in using Visual Studio 2008 targeting Outlook 2003 as the minimum version. Works fine on Outlook 2003, 2007, and 2010. However, it does not load in Outlook 2013. I see the dreaded message in Outlook "Not loaded. A runtime error occurred during the loading of the COM Add-in."
Should it load? Is the 2013 PIA compatible with an Add-In built for 2003? (Talking 32-bit Outlook here.)
I've turned on the VSTO environment warning flag, but no message. Tried turning on Fusion logging too, no helpful info found there either.