I’ve developed a small Add-in for Visual Studio and kept running into a rather odd problem. During the testing of the addin it would work fine, I’d see my Addin in the addin manager and I’d get a couple of new menu items showing under the tools menu. However, when I built a release version, copied the files into my VisualStudio 2008\Addins folder I could only see the Addin in the manager but not the menu items. Turns out that I just needed to get rid of the XXXFor Testing.Add file from the Addins folder. Well I renamed it to make it easier to debug later, but I certainly confused me for a while, I think the debug version should have a different name, which you can do by editing the .addin file.