You can now clear the active user for ownership history. See #1790.

src/blenderbim/blenderbim/tool/ifc.py

@@ -37,7 +37,8 @@ class Ifc(blenderbim.core.tool.Ifc):
 
     @classmethod
     def get_schema(cls):
-        return IfcStore.get_file().schema
+        if IfcStore.get_file():
+            return IfcStore.get_file().schema
 
     @classmethod
     def get_entity(cls, obj):

src/blenderbim/blenderbim/tool/owner.py

@@ -30,6 +30,10 @@ class Owner(blenderbim.core.tool.Owner):
     def get_user(cls):
         if bpy.context.scene.BIMOwnerProperties.active_user_id:
             return tool.Ifc.get().by_id(bpy.context.scene.BIMOwnerProperties.active_user_id)
+        elif tool.Ifc.get_schema() == "IFC2X3":
+            users = tool.Ifc.get().by_type("IfcPersonAndOrganization")
+            if users:
+                return users[0]
 
     @classmethod
     def clear_user(cls):