diff --git a/server/src/com/cloud/vm/UserVmManagerImpl.java b/server/src/com/cloud/vm/UserVmManagerImpl.java
index 251c203f13b..73d46028e29 100755
--- a/server/src/com/cloud/vm/UserVmManagerImpl.java
+++ b/server/src/com/cloud/vm/UserVmManagerImpl.java
@@ -3488,8 +3488,8 @@ public class UserVmManagerImpl extends ManagerBase implements UserVmManager, Use
     public void collectVmDiskStatistics (UserVmVO userVm) {
         // support KVM only util 2013.06.25
         if (!userVm.getHypervisorType().equals(HypervisorType.KVM))
-            return;        
-    	// Collect vm disk statistics from host before stopping Vm
+            return;
+    	s_logger.debug("Collect vm disk statistics from host before stopping Vm");
     	long hostId = userVm.getHostId();
     	List<String> vmNames = new ArrayList<String>();
     	vmNames.add(userVm.getInstanceName());
@@ -3511,8 +3511,9 @@ public class UserVmManagerImpl extends ManagerBase implements UserVmManager, Use
             try {
                 txn.start();
                 HashMap<String, List<VmDiskStatsEntry>> vmDiskStatsByName = diskStatsAnswer.getVmDiskStatsMap();
+                if (vmDiskStatsByName == null)
+                    return;
                 List<VmDiskStatsEntry> vmDiskStats = vmDiskStatsByName.get(userVm.getInstanceName());
-
                 if (vmDiskStats == null)
 		    return;
 
@@ -4980,7 +4981,7 @@ public class UserVmManagerImpl extends ManagerBase implements UserVmManager, Use
     @Override
     public void prepareStop(VirtualMachineProfile<UserVmVO> profile) {
         UserVmVO vm = _vmDao.findById(profile.getId());
-        if (vm.getState() == State.Running)
+        if (vm != null && vm.getState() == State.Stopping)
             collectVmDiskStatistics(vm);
     }