If you download the CHECK DUPLICATES from the GOODIES website (check your HELP menu in archicad) you can load this little API that searches for and deletes duplicates.
Duane
Visual Frontiers
AC25 :|: AC26 :|: AC27
:|: Enscape3.4:|:TwinMotion
DellXPS 4.7ghz i7:|: 8gb GPU 1070ti / Alienware M18 Laptop