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.