diff --git a/engine/api/src/org/apache/cloudstack/storage/command/AttachAnswer.java b/engine/api/src/org/apache/cloudstack/storage/command/AttachAnswer.java
index 1ddcd7dce8d..092ec63df44 100644
--- a/engine/api/src/org/apache/cloudstack/storage/command/AttachAnswer.java
+++ b/engine/api/src/org/apache/cloudstack/storage/command/AttachAnswer.java
@@ -26,8 +26,9 @@ public class AttachAnswer extends Answer {
     public AttachAnswer() {
         super(null);
     }
-    
+
     public AttachAnswer(DiskTO disk) {
+        super(null);
         this.setDisk(disk);
     }
     public AttachAnswer(String errMsg) {