diff --git a/React/Modules/RCTUIManager.m b/React/Modules/RCTUIManager.m
index 9124494b5fd..486bc9845b1 100644
--- a/React/Modules/RCTUIManager.m
+++ b/React/Modules/RCTUIManager.m
@@ -1656,6 +1656,8 @@ static UIView *_jsResponder;
 
 + (UIView *)JSResponder
 {
+  RCTErrorNewArchitectureValidation(
+      RCTNotAllowedInAppWideFabric, @"RCTUIManager", @"Please migrate this legacy surface to Fabric.");
   return _jsResponder;
 }