I have come across several issues with using the GAT.  One of them is when I go to add some new artifact (a new project, solution, T4 template) without first unregistering the package.  I can just go and register the guidance package, however, sometimes, it gets corrupted.  If that happens, see my post on Uninstalling a GAT Package Manually.  What makes this interesting, is that the xml of solutions and projects looks to be inspected during the unregister process for references.

To get an error unregistering, do the following.

  1. Register the GAT
  2. Add a new project template (.vstemplate) below the projects folder
  3. Create a TemplateReference in your base solution to a new project
  4. Try to unregister the GAT
  5. Register the GAT again. Then unregister, it should work.


This little quirk has bothered me for some time because of the way I was creating new items for the GAT.  Just thought I would pass the information along.