Opening a 2008–2010 project in a modern Archicad version can lead to missing GDL (Geometric Description Language) objects.
You accidentally downloaded a library from Archicad 13 or 14. Solution: Verify the file name. Legitimate Archicad 12 libraries often have "12" in the filename or date stamps from 2008-2009. Archicad 12 Library Download
: Scans your project to identify exactly which GDL (Geometric Description Language) objects are missing. Opening a 2008–2010 project in a modern Archicad