Hello,
Some of your tool [wall, object, slab, etc.] might have that property
linked 'Individually' or 'By Criteria' as default -> check thru the toolbox 'Listing and Labeling'.
If it's found there 'Individually' it is hard to get rid of. Even if the link is greyed the library manager gives an error. Better to create a dummy property in your common library and link to that one.
If it's found 'By Criteria' then change those settings (ArchiCAD 11 manual page 329).
Hope this helps.
--
Juha