diff --git a/plugins/hypervisors/vmware/src/com/cloud/hypervisor/vmware/resource/VmwareResource.java b/plugins/hypervisors/vmware/src/com/cloud/hypervisor/vmware/resource/VmwareResource.java
index ade46d2876a..37ed0559a69 100755
--- a/plugins/hypervisors/vmware/src/com/cloud/hypervisor/vmware/resource/VmwareResource.java
+++ b/plugins/hypervisors/vmware/src/com/cloud/hypervisor/vmware/resource/VmwareResource.java
@@ -4945,9 +4945,12 @@ public class VmwareResource implements StoragePoolResource, ServerResource, Vmwa
                     if (cmd.isAttach()) {
                         vmMo.mountToolsInstaller();
                     } else {
-                        try {
-                            vmMo.unmountToolsInstaller();
-                        } catch (Throwable e) {
+                        try{
+                            if (!vmMo.unmountToolsInstaller()) {
+                                return new Answer(cmd, false,
+                                        "Failed to unmount vmware-tools installer ISO as the corresponding CDROM device is locked by VM. Please unmount the CDROM device inside the VM and ret-try.");
+                            }
+                        }catch(Throwable e){
                             vmMo.detachIso(null);
                         }
                     }
diff --git a/plugins/hypervisors/vmware/src/com/cloud/storage/resource/VmwareStorageProcessor.java b/plugins/hypervisors/vmware/src/com/cloud/storage/resource/VmwareStorageProcessor.java
index abb673328d3..e13362d1331 100644
--- a/plugins/hypervisors/vmware/src/com/cloud/storage/resource/VmwareStorageProcessor.java
+++ b/plugins/hypervisors/vmware/src/com/cloud/storage/resource/VmwareStorageProcessor.java
@@ -1263,9 +1263,11 @@ public class VmwareStorageProcessor implements StorageProcessor {
                     if (isAttach) {
                         vmMo.mountToolsInstaller();
                     } else {
-                        try {
-                            vmMo.unmountToolsInstaller();
-                        } catch (Throwable e) {
+                        try{
+                            if (!vmMo.unmountToolsInstaller()) {
+                                return new AttachAnswer("Failed to unmount vmware-tools installer ISO as the corresponding CDROM device is locked by VM. Please unmount the CDROM device inside the VM and ret-try.");
+                            }
+                        } catch(Throwable e){
                             vmMo.detachIso(null);
                         }
                     }
diff --git a/vmware-base/src/com/cloud/hypervisor/vmware/mo/VirtualMachineMO.java b/vmware-base/src/com/cloud/hypervisor/vmware/mo/VirtualMachineMO.java
index b23b0ff6d07..8c5f0a6d255 100644
--- a/vmware-base/src/com/cloud/hypervisor/vmware/mo/VirtualMachineMO.java
+++ b/vmware-base/src/com/cloud/hypervisor/vmware/mo/VirtualMachineMO.java
@@ -2345,11 +2345,13 @@ public class VirtualMachineMO extends BaseMO {
         _context.getService().mountToolsInstaller(_mor);
     }
 
-    public void unmountToolsInstaller() throws Exception {
+    public boolean unmountToolsInstaller() throws Exception {
         int i = 1;
         // Monitor VM questions
         final Boolean[] flags = {false};
         final VirtualMachineMO vmMo = this;
+        final boolean[] encounterQuestion = new boolean[1];
+        encounterQuestion[0] = false;
         Future<?> future = MonitorServiceExecutor.submit(new Runnable() {
             @Override
             public void run() {
@@ -2360,6 +2362,7 @@ public class VirtualMachineMO extends BaseMO {
                         VirtualMachineRuntimeInfo runtimeInfo = vmMo.getRuntimeInfo();
                         VirtualMachineQuestionInfo question = runtimeInfo.getQuestion();
                         if (question != null) {
+                            encounterQuestion[0] = true;
                             if (s_logger.isTraceEnabled()) {
                                 s_logger.trace("Question id: " + question.getId());
                                 s_logger.trace("Question text: " + question.getText());
@@ -2425,6 +2428,13 @@ public class VirtualMachineMO extends BaseMO {
             flags[0] = true;
             future.cancel(true);
         }
+        if (encounterQuestion[0]) {
+            s_logger.warn("cdrom is locked by VM. Failed to detach the ISO.");
+            return false;
+        } else {
+            s_logger.info("Successfully unmounted tools installer from VM.");
+            return true;
+        }
     }
 
     public void redoRegistration(ManagedObjectReference morHost) throws Exception {