Be careful to purge families from a Project file by using the Purging feature. Purging removes all unused types of a family, however if you require a type (that was purged out) within a family then re-loading the family will not simply add it back in.
I prefer to delete all unused families manually in a Project file from the Project browser, one by one, and I don’t delete types within a family that are not in use.
Use “select all instances” when using the Project Browser to see if a family is in use before deleting it from the Project file. If it is in use Revit® will automatically give you a warning message to say you are about the delete elements from you model. The warning message will give you the option to select CANCEL and you can then proceed to the next family in the list.
I recommend that you remove any shortcut keys for Purging from documenters’ local Keyboard shortcut txt files.
© Copyright Reserved by Michelle Louw (Excerpt from My speaker notes at National Revit Technology Conference 2008.)