While discussing an interesting baluster-with-lighting family, Steve reminds us that “Revit hates switching between shared and not shared status.”
You have to follow a strict process of deleting and / or renaming affected families that exist in the project if you wish to switch them from Shared to non-Shared, or vice-versa.
If you want to read the rest of Steve’s, post, here is a link:
Revit OpEd: Dept. of Quirky – Baluster with Light Fixture