diff --git a/platform/platform-impl/src/com/intellij/openapi/project/DumbServiceImpl.java b/platform/platform-impl/src/com/intellij/openapi/project/DumbServiceImpl.java
index eebb9b3e98eb..0a345cf07f7f 100644
--- a/platform/platform-impl/src/com/intellij/openapi/project/DumbServiceImpl.java
+++ b/platform/platform-impl/src/com/intellij/openapi/project/DumbServiceImpl.java
@@ -268,6 +268,10 @@ public class DumbServiceImpl extends DumbService {
       assert !application.isReadAccessAllowed();
     }
 
+    if (!isDumb()) {
+      return;
+    }
+
     final Semaphore semaphore = new Semaphore();
     semaphore.down();
     runWhenSmart(new Runnable() {