diff --git a/src/blenderbim/blenderbim/bim/module/aggregate/operator.py b/src/blenderbim/blenderbim/bim/module/aggregate/operator.py
index bf336ad69b..9e26e78db0 100644
--- a/src/blenderbim/blenderbim/bim/module/aggregate/operator.py
+++ b/src/blenderbim/blenderbim/bim/module/aggregate/operator.py
@@ -91,10 +91,11 @@ class BIM_OT_aggregate_unassign_object(bpy.types.Operator, Operator):
             )
             
             # Removes Pset related to Linked Aggregates
-            pset = ifcopenshell.util.element.get_pset(element, 'BBIM_Linked_Aggregate')
-            if pset:
-                pset = tool.Ifc.get().by_id(pset["id"])
-                ifcopenshell.api.run("pset.remove_pset", tool.Ifc.get(), pset=pset)
+            if not element.is_a('IfcElementAssembly'):
+                pset = ifcopenshell.util.element.get_pset(element, 'BBIM_Linked_Aggregate')
+                if pset:
+                    pset = tool.Ifc.get().by_id(pset["id"])
+                    ifcopenshell.api.run("pset.remove_pset", tool.Ifc.get(), pset=pset)
 
 
 class BIM_OT_enable_editing_aggregate(bpy.types.Operator, Operator):