André:
If you imported an older Work Environment, the Attribute Manager will not appear as they changed the command. If you go to Work Environment > Command Layout Schemes > Menus, and set the List to All new commands in alphabetical order, you will find the new Attribute Manger... command; add it to your WE.
You should add a Signature to your Profile (click the Profile button near the top of this page) with your ArchiCAD version and operating system (see mine for an example) for more accurate help in this forum.
David
