What's different on the 2 machines? Are you deploying all required
dependencies of your addin (including the VSTO runtime and Framework, the
Office and Outlook PIA's, etc.)?

Take a look at the following troubleshooting information for managed code
addins:

http://blogs.msdn.com/vsod/archive/2...-failures.aspx

--
Ken Slovak
[MVP - Outlook]
http://www.slovaktech.com
Author: Professional Programming Outlook 2007.
Reminder Manager, Extended Reminders, Attachment Options.
http://www.slovaktech.com/products.htm


"Mark B" wrote in message
...
Our VSTO 2007 Addin is being immediately auto-disabled on one machine but
not another on installation.

Anyone know why this would be?