Custom Ribbon in VSTO Addin for Outlook 2010 doesn't display
To get your ribbon displayed, on the base ribbon in your code change the RibbonType
property to be Microsoft.Outlook.Explorer
.
What fixed it for me (without starting a new project), in the Ribbon1.vb ribbon design, I clicked on the the Ribbon1 name above the ribbons 'File' button, in the properties pane, clicked on tabs (collection), under the heading 'Design' I changed the name (from Tab1) to something else.
Clicked ok, tested by clicking F5 and it worked. Hope this helps someone else.