I have an exception when I try to repair or to remove the GAT, because there is problems with registered guidance packages which don't exist yet.
So I tried to manually unregister all the guidance package, following the instructions on the Clarius's Blog. I unregistered all the guidance packages found in the manifest file (RecipeFramework.xml). But if there is other registered guidance packages unknown (because I have no more the files), it is impossible to unregister them because I don't know their name and GUID.
So it is always impossible to repair or remove GAT ! The exception said "The manifest file doesn't contain an entry for the guidance package Guidance Package Development".
Usually, in this case, you install again the software over the same software which works bad, and you can after uninstall it properly. But here, it is impossible to reinstall the GAT.
I think the GAT uninstallation will have to manage the bad unregistered guidance package and clean the registry.
Thanks