The newsgroups are dead, the replacements are the forums. This one is
probably the most appropriate:
You need to supply more information.
What language is this written in? How is it being registered? Is it
registered on the Outlook 2010 machine? Are you hitting at least
OnConnection()? Is this a VSTO addin or shared or unmanaged? Is it listed as
disabled or do you have load errors?
You can post here or in the forum but you'll need to supply that information
before anyone can begin to figure things out. It could be something as
simple as not allowing a version higher than "12" if you check Outlook
version, or it could be something more.
FWIW, all of my 2003/2007 addins run without problems in 2010 32-bit code.
[MVP - Outlook]
Author: Professional Programming Outlook 2007.
Reminder Manager, Extended Reminders, Attachment Options.