diff --git a/core/src/test/java/hudson/LauncherTest.java b/core/src/test/java/hudson/LauncherTest.java
index 429d107908..ccdc065e6a 100644
--- a/core/src/test/java/hudson/LauncherTest.java
+++ b/core/src/test/java/hudson/LauncherTest.java
@@ -51,7 +51,8 @@ public class LauncherTest extends ChannelTestCase {
         assertTrue(p.join()!=0);
         long end = System.currentTimeMillis();
         assertTrue("join finished promptly", (end - start < 5000));
-        french.call(NOOP); // this only returns after the other side of the channel has finished executing cancellation 
+        french.call(NOOP); // this only returns after the other side of the channel has finished executing cancellation
+        Thread.sleep(2000); // more delay to make sure it's gone
         assertNull("process should be gone",ProcessTree.get().get(Integer.parseInt(FileUtils.readFileToString(tmp).trim())));
 
         // Manual version of test: set up instance w/ one slave. Now in script console