diff --git a/pkg/dev_compiler/lib/src/command/command.dart b/pkg/dev_compiler/lib/src/command/command.dart
index b557094358b..5cc88c5db2e 100644
--- a/pkg/dev_compiler/lib/src/command/command.dart
+++ b/pkg/dev_compiler/lib/src/command/command.dart
@@ -374,7 +374,8 @@ Future<CompilerResult> _compile(List<String> args,
           lastAcceptedComponent, compiledLibraries);
       if (rejectionReasons.isNotEmpty) {
         throw StateError(
-            'Hot reload rejected due to:\n${rejectionReasons.join('\n')}');
+            'Hot reload rejected due to:\n${rejectionReasons.join('\n')}\n'
+            'Use hot restart instead.');
       }
     }
     var sink = File(reloadDeltaKernel).openWrite();
diff --git a/pkg/frontend_server/lib/src/javascript_bundle.dart b/pkg/frontend_server/lib/src/javascript_bundle.dart
index a36402e81b5..369b468c7c9 100644
--- a/pkg/frontend_server/lib/src/javascript_bundle.dart
+++ b/pkg/frontend_server/lib/src/javascript_bundle.dart
@@ -90,7 +90,11 @@ class IncrementalJavaScriptBundler {
       // connected component graph.
       final List<String> errors = _deltaInspector.compareGenerations(
           lastFullComponent, partialComponent);
-      if (errors.isNotEmpty) throw new Exception(errors.join('/n'));
+      if (errors.isNotEmpty) {
+        throw new Exception(errors.join('/n') +
+            '\nHot reload rejected due to unsupported changes. '
+                'Use hot restart instead.');
+      }
     }
     _currentComponent = partialComponent;
     _updateFullComponent(lastFullComponent, partialComponent);