diff --git a/bacnet-stack/demo/object/bi.c b/bacnet-stack/demo/object/bi.c
index 57ff2845..5f3b800a 100644
--- a/bacnet-stack/demo/object/bi.c
+++ b/bacnet-stack/demo/object/bi.c
@@ -479,10 +479,19 @@ bool Binary_Input_Write_Property(
                 }
             }
             break;
-        default:
+        case PROP_OBJECT_IDENTIFIER:
+        case PROP_OBJECT_NAME:
+        case PROP_DESCRIPTION:
+        case PROP_OBJECT_TYPE:
+        case PROP_STATUS_FLAGS:
+        case PROP_EVENT_STATE:
             wp_data->error_class = ERROR_CLASS_PROPERTY;
             wp_data->error_code = ERROR_CODE_WRITE_ACCESS_DENIED;
             break;
+        default:
+            wp_data->error_class = ERROR_CLASS_PROPERTY;
+            wp_data->error_code = ERROR_CODE_UNKNOWN_PROPERTY;
+            break;
     }
 
     return status;
diff --git a/bacnet-stack/demo/object/csv.c b/bacnet-stack/demo/object/csv.c
index f8c6dd73..7662158a 100644
--- a/bacnet-stack/demo/object/csv.c
+++ b/bacnet-stack/demo/object/csv.c
@@ -423,10 +423,19 @@ bool CharacterString_Value_Write_Property(
                     object_instance, value.type.Boolean);
             }
             break;
-        default:
+        case PROP_OBJECT_IDENTIFIER:
+        case PROP_OBJECT_NAME:
+        case PROP_DESCRIPTION:
+        case PROP_OBJECT_TYPE:
+        case PROP_STATUS_FLAGS:
+        case PROP_EVENT_STATE:
             wp_data->error_class = ERROR_CLASS_PROPERTY;
             wp_data->error_code = ERROR_CODE_WRITE_ACCESS_DENIED;
             break;
+        default:
+            wp_data->error_class = ERROR_CLASS_PROPERTY;
+            wp_data->error_code = ERROR_CODE_UNKNOWN_PROPERTY;
+            break;
     }
 
     return status;
diff --git a/bacnet-stack/demo/object/lsp.c b/bacnet-stack/demo/object/lsp.c
index 93954986..b2b3a00d 100644
--- a/bacnet-stack/demo/object/lsp.c
+++ b/bacnet-stack/demo/object/lsp.c
@@ -361,10 +361,28 @@ bool Life_Safety_Point_Write_Property(
                     value.type.Boolean;
             }
             break;
-        default:
+
+
+
+        case PROP_OBJECT_IDENTIFIER:
+        case PROP_OBJECT_NAME:
+        case PROP_DESCRIPTION:
+        case PROP_OBJECT_TYPE:
+        case PROP_PRESENT_VALUE:
+        case PROP_TRACKING_VALUE:
+        case PROP_STATUS_FLAGS:
+        case PROP_EVENT_STATE:
+        case PROP_RELIABILITY:
+        case PROP_ACCEPTED_MODES:
+        case PROP_SILENCED:
+        case PROP_OPERATION_EXPECTED:
             wp_data->error_class = ERROR_CLASS_PROPERTY;
             wp_data->error_code = ERROR_CODE_WRITE_ACCESS_DENIED;
             break;
+        default:
+            wp_data->error_class = ERROR_CLASS_PROPERTY;
+            wp_data->error_code = ERROR_CODE_UNKNOWN_PROPERTY;
+            break;
     }
 
     return status;