Dave Donaldson

Here's another tip when creating Visual Studio add-ins:

Exclude All Dependency Files
When you first go to create an add-in, you'll most likely use the Visual Studio .NET Add-In project template. This will actually create two projects for you - the add-in project and its setup project. The setup project has a folder named Detected Dependencies that contains a list of files and assemblies needed for installing the add-in. Apparently, these dependencies have caused some major headaches for people, so it's recommended to mark all these files as excluded from the project.

If you think about it, it makes sense to do this because all these dependencies must already be on your system to begin with in order for Visual Studio to work, and if Visual Studio doesn't work, your add-in certainly isn't going to be of much use. The interesting thing here is that all but two of the dependencies, Extensibility.dll and Office.dll, are marked as excluded by default. So take the right precaution and mark these other two assemblies as excluded and you'll be certain your add-in won't screw up anyone's installation of Visual Studio.

Thanks to James for pointing me to the above post.