diff --git a/src/blenderbim/blenderbim/bim/module/geometry/operator.py b/src/blenderbim/blenderbim/bim/module/geometry/operator.py
index 385ca383c9..2fecf1b793 100644
--- a/src/blenderbim/blenderbim/bim/module/geometry/operator.py
+++ b/src/blenderbim/blenderbim/bim/module/geometry/operator.py
@@ -714,6 +714,10 @@ class OverrideOutlinerDelete(bpy.types.Operator):
             else:
                 bpy.data.objects.remove(obj)
         for collection in collections_to_delete:
+            # Removing an aggregate object would also remove it's collection
+            # making the collection data-block invalid.
+            if not tool.Blender.is_valid_data_block(collection):
+                continue
             bpy.data.collections.remove(collection)
         if self.is_batch:
             old_file = tool.Ifc.get()
diff --git a/src/blenderbim/blenderbim/tool/blender.py b/src/blenderbim/blenderbim/tool/blender.py
index 3726911796..a58392b16c 100644
--- a/src/blenderbim/blenderbim/tool/blender.py
+++ b/src/blenderbim/blenderbim/tool/blender.py
@@ -196,6 +196,21 @@ class Blender(blenderbim.core.tool.Blender):
             return False
         return False
 
+    @classmethod
+    def is_valid_data_block(cls, data_block: bpy.types.ID) -> bool:
+        """Check if Blender data-block is still valid.
+
+        If Blender data-block (e.g. an Object) is removed then it's
+        python object gets invalidated and accessing any of it's attributes
+        leads to ReferenceError: StructRNA of type Object has been removed.
+        This method helps avoiding try / except ReferenceError constructions.
+        """
+        try:
+            data_block.bl_rna
+            return True
+        except ReferenceError:
+            return False
+
     @classmethod
     def show_info_message(cls, text: str, message_type: Literal["INFO", "ERROR"] = "INFO") -> None:
         """useful for showing error messages outside blender operators