64-bit Win7. Local drive for development. I'm not sure how I should "clean" my machine. I'm not quite ready to wipe the hard drive and reinstall everything. 🙂 Do the pdb files that come with the dlls mean I can stop inside CloseGeodatabase and see where it's stuck? I haven't been able to so far by telling VS the location of the symbol files. Currently when I break in the debugger it stops in thread-related code (lock) or in the function CatalogRegistry::CatalogRef::Release() under CatalogRegistry::Unregister() . That much in can see in the call stack.