diff --git a/src/bonsai/bonsai/bim/module/pset/operator.py b/src/bonsai/bonsai/bim/module/pset/operator.py
index 5870547bce..24662bee04 100644
--- a/src/bonsai/bonsai/bim/module/pset/operator.py
+++ b/src/bonsai/bonsai/bim/module/pset/operator.py
@@ -440,5 +440,8 @@ class AddProposedProp(bpy.types.Operator):
     prop_value: bpy.props.StringProperty()
 
     def execute(self, context):
-        core.add_proposed_prop(tool.Pset, self.obj, self.obj_type, self.prop_name, self.prop_value)
+        res = core.add_proposed_prop(tool.Pset, self.obj, self.obj_type, self.prop_name, self.prop_value)
+        if res:
+            self.report({"ERROR"}, res)
+            return {"CANCELLED"}
         return {"FINISHED"}
diff --git a/src/bonsai/bonsai/core/pset.py b/src/bonsai/bonsai/core/pset.py
index c2b87836df..c96e5177ff 100644
--- a/src/bonsai/bonsai/core/pset.py
+++ b/src/bonsai/bonsai/core/pset.py
@@ -89,9 +89,12 @@ def enable_pset_editing(
         pset_tool.enable_proposed_pset(props, pset_name, pset_type, has_template)
 
 
-def add_proposed_prop(pset: tool.Pset, obj_name: str, obj_type: tool.Ifc.OBJECT_TYPE, name: str, value: Any) -> None:
+def add_proposed_prop(
+    pset: tool.Pset, obj_name: str, obj_type: tool.Ifc.OBJECT_TYPE, name: str, value: Any
+) -> Union[None, str]:
     props = pset.get_pset_props(obj_name, obj_type)
-    pset.add_proposed_property(name, pset.cast_string_to_primitive(value), props)
+    res = pset.add_proposed_property(name, pset.cast_string_to_primitive(value), props)
+    return res
 
 
 def unshare_pset(
diff --git a/src/bonsai/bonsai/tool/pset.py b/src/bonsai/bonsai/tool/pset.py
index e5436513db..dcfa111872 100644
--- a/src/bonsai/bonsai/tool/pset.py
+++ b/src/bonsai/bonsai/tool/pset.py
@@ -297,9 +297,9 @@ class Pset(bonsai.core.tool.Pset):
         return bonsai.bim.schema.ifc.psetqto.get_by_name(name)
 
     @classmethod
-    def add_proposed_property(cls, name: str, value: Any, props: bpy.types.PropertyGroup) -> None:
+    def add_proposed_property(cls, name: str, value: Any, props: bpy.types.PropertyGroup) -> Union[None, str]:
         if props.properties.get(name):
-            return
+            return f"Property '{name}' already exists."
         prop = props.properties.add()
         prop.name = name
         metadata = prop.metadata