Are you now using a different library then when you created the Favorites?
Library Parts are identified by a Global Unique Identifier (GUID) not by name since AC12.
When a Favorite is grayed out in the Favorites Palette it means that ArchiCAD does not find the library part the Favorite refers to.
If the above is the case then what you should do is first load the Library you want to work with and then modify/recreate the Favorites.
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