diff --git a/sandbox-apis/virtualbox/src/main/java/org/jclouds/virtualbox/util/MachineUtils.java b/sandbox-apis/virtualbox/src/main/java/org/jclouds/virtualbox/util/MachineUtils.java
index 0d1bc298ca..1ebf921860 100644
--- a/sandbox-apis/virtualbox/src/main/java/org/jclouds/virtualbox/util/MachineUtils.java
+++ b/sandbox-apis/virtualbox/src/main/java/org/jclouds/virtualbox/util/MachineUtils.java
@@ -25,6 +25,7 @@ import org.virtualbox_4_1.ISession;
 import org.virtualbox_4_1.LockType;
 import org.virtualbox_4_1.VBoxException;
 import org.virtualbox_4_1.VirtualBoxManager;
+import org.virtualbox_4_1.jaxws.SessionState;
 
 import com.google.common.base.Function;
 
@@ -131,4 +132,52 @@ public class MachineUtils {
          return null;
       }
    }
+   
+   /**
+    * Unlocks the machine and executes the given function using the machine matching the given id.
+    * Since the machine is unlocked it is possible to delete the IMachine.
+    * <p/>
+    *
+    * @param manager   the VirtualBoxManager
+    * @param machineId the id of the machine
+    * @param function  the function to execute
+    * @return the result from applying the function to the machine.
+    */
+   public static <T> T unlockMachineAndApply(VirtualBoxManager manager, final String machineId,
+                                           final Function<IMachine, T> function) {
+      try {
+         ISession session = manager.getSessionObject();
+         IMachine immutableMachine = manager.getVBox().findMachine(machineId);
+         if(immutableMachine.getSessionState().equals(SessionState.LOCKED))
+            session.unlockMachine();
+         
+         return function.apply(immutableMachine);
+         
+      } catch (VBoxException e) {
+         throw new RuntimeException(String.format("error applying %s to %s: %s", function, machineId,
+                 e.getMessage()), e);
+      }
+   }
+   
+   /**
+    * Unlocks the machine and executes the given function, if the machine is registered.
+    * Since the machine is unlocked it is possible to delete the machine.
+    * <p/>
+    *
+    * @param manager   the VirtualBoxManager
+    * @param machineId the id of the machine
+    * @param function  the function to execute
+    * @return the result from applying the function to the session.
+    */
+   public static <T> T unlockMachineAndApplyOrReturnNullIfNotRegistered(VirtualBoxManager manager, String machineId,
+                                                    Function<IMachine, T> function) {
+      try {
+         return unlockMachineAndApply(manager, machineId, function);
+      } catch (RuntimeException e) {
+         VBoxException vbex = Throwables2.getFirstThrowableOfType(e, VBoxException.class);
+         if (vbex != null && vbex.getMessage().indexOf("not find a registered") == -1)
+            throw e;
+         return null;
+      }
+   }
 }
diff --git a/sandbox-apis/virtualbox/src/test/java/org/jclouds/virtualbox/functions/CloneAndRegisterMachineFromIsoIfNotAlreadyExistsLiveTest.java b/sandbox-apis/virtualbox/src/test/java/org/jclouds/virtualbox/functions/CloneAndRegisterMachineFromIsoIfNotAlreadyExistsLiveTest.java
index 3bec904af8..2103222493 100644
--- a/sandbox-apis/virtualbox/src/test/java/org/jclouds/virtualbox/functions/CloneAndRegisterMachineFromIsoIfNotAlreadyExistsLiveTest.java
+++ b/sandbox-apis/virtualbox/src/test/java/org/jclouds/virtualbox/functions/CloneAndRegisterMachineFromIsoIfNotAlreadyExistsLiveTest.java
@@ -20,9 +20,8 @@
 package org.jclouds.virtualbox.functions;
 
 import static org.jclouds.virtualbox.experiment.TestUtils.computeServiceForLocalhostAndGuest;
-import static org.jclouds.virtualbox.util.MachineUtils.lockMachineAndApplyOrReturnNullIfNotRegistered;
+import static org.jclouds.virtualbox.util.MachineUtils.unlockMachineAndApplyOrReturnNullIfNotRegistered;
 import static org.testng.Assert.assertEquals;
-import static org.virtualbox_4_1.LockType.Write;
 
 import org.jclouds.compute.ComputeServiceContext;
 import org.jclouds.domain.Credentials;
@@ -49,11 +48,11 @@ public class CloneAndRegisterMachineFromIsoIfNotAlreadyExistsLiveTest extends
 
    private static final boolean IS_LINKED_CLONE = true;
    private String vmId = "jclouds-image-iso-1";
-   private String osTypeId = "DEBIAN";
+   private String osTypeId = "";
    private String guestId = "guest";
    private String hostId = "host";
 
-   private String vmName = "jclouds-image-virtualbox-iso-to-machine-test";
+   private String vmName = "jclouds-virtualbox-clone-test";
    private String cloneName = vmName + "_clone";
    private VmSpec clonedVmSpec;
 
@@ -84,7 +83,8 @@ public class CloneAndRegisterMachineFromIsoIfNotAlreadyExistsLiveTest extends
             manager, workingDir, clonedVmSpec, IS_LINKED_CLONE).apply(master);
       assertEquals(clone.getName(), clonedVmSpec.getVmName());
       for (VmSpec spec : ImmutableSet.of(clonedVmSpec, new IMachineToVmSpec().apply(master)))
-         lockMachineAndApplyOrReturnNullIfNotRegistered(manager, Write, spec.getVmName(), new UnregisterMachineIfExistsAndDeleteItsMedia(spec));
+            unlockMachineAndApplyOrReturnNullIfNotRegistered(manager, spec.getVmName(), new UnregisterMachineIfExistsAndDeleteItsMedia(spec));
+
    }
 
    private IMachine getMasterNode(VirtualBoxManager manager,
diff --git a/sandbox-apis/virtualbox/src/test/java/org/jclouds/virtualbox/functions/CreateAndRegisterMachineFromIsoIfNotAlreadyExistsLiveTest.java b/sandbox-apis/virtualbox/src/test/java/org/jclouds/virtualbox/functions/CreateAndRegisterMachineFromIsoIfNotAlreadyExistsLiveTest.java
index e3bcadc926..66f6ac7217 100644
--- a/sandbox-apis/virtualbox/src/test/java/org/jclouds/virtualbox/functions/CreateAndRegisterMachineFromIsoIfNotAlreadyExistsLiveTest.java
+++ b/sandbox-apis/virtualbox/src/test/java/org/jclouds/virtualbox/functions/CreateAndRegisterMachineFromIsoIfNotAlreadyExistsLiveTest.java
@@ -19,10 +19,9 @@
 
 package org.jclouds.virtualbox.functions;
 
-import static org.jclouds.virtualbox.util.MachineUtils.lockMachineAndApplyOrReturnNullIfNotRegistered;
+import static org.jclouds.virtualbox.util.MachineUtils.unlockMachineAndApplyOrReturnNullIfNotRegistered;
 import static org.testng.Assert.assertEquals;
 import static org.testng.Assert.fail;
-import static org.virtualbox_4_1.LockType.Write;
 
 import org.jclouds.virtualbox.BaseVirtualBoxClientLiveTest;
 import org.jclouds.virtualbox.domain.ErrorCode;
@@ -70,14 +69,12 @@ public class CreateAndRegisterMachineFromIsoIfNotAlreadyExistsLiveTest extends
       VmSpec launchSpecification = VmSpec.builder().id(vmName).name(vmName)
             .memoryMB(512).controller(ideController).cleanUpMode(mode)
             .osTypeId("Debian").forceOverwrite(true).build();
-      lockMachineAndApplyOrReturnNullIfNotRegistered(manager, Write, launchSpecification.getVmName(), new UnregisterMachineIfExistsAndDeleteItsMedia(launchSpecification));
-
+      unlockMachineAndApplyOrReturnNullIfNotRegistered(manager, launchSpecification.getVmName(), new UnregisterMachineIfExistsAndDeleteItsMedia(launchSpecification));
       IMachine debianNode = new CreateAndRegisterMachineFromIsoIfNotAlreadyExists(
             manager, workingDir).apply(launchSpecification);
       IMachine machine = manager.getVBox().findMachine(vmName);
       assertEquals(debianNode.getName(), machine.getName());
-      lockMachineAndApplyOrReturnNullIfNotRegistered(manager, Write, launchSpecification.getVmName(), new UnregisterMachineIfExistsAndDeleteItsMedia(launchSpecification));
-
+      unlockMachineAndApplyOrReturnNullIfNotRegistered(manager, launchSpecification.getVmName(), new UnregisterMachineIfExistsAndDeleteItsMedia(launchSpecification));
    }
 
    @Test
@@ -86,8 +83,8 @@ public class CreateAndRegisterMachineFromIsoIfNotAlreadyExistsLiveTest extends
       VmSpec launchSpecification = VmSpec.builder().id(vmName).name(vmName)
             .memoryMB(512).controller(ideController).cleanUpMode(mode)
             .osTypeId("SomeWeirdUnknownOs").forceOverwrite(true).build();
-      lockMachineAndApplyOrReturnNullIfNotRegistered(manager, Write, launchSpecification.getVmName(), new UnregisterMachineIfExistsAndDeleteItsMedia(launchSpecification));
-
+      unlockMachineAndApplyOrReturnNullIfNotRegistered(manager, launchSpecification.getVmName(), new UnregisterMachineIfExistsAndDeleteItsMedia(launchSpecification));
+      //new UnregisterMachineIfExistsAndDeleteItsMedia(launchSpecification).apply(manager.getVBox().findMachine(vmName));
       try {
          new CreateAndRegisterMachineFromIsoIfNotAlreadyExists(manager, workingDir)
                .apply(launchSpecification);
diff --git a/sandbox-apis/virtualbox/src/test/java/org/jclouds/virtualbox/functions/CreateMediumIfNotAlreadyExistsLiveTest.java b/sandbox-apis/virtualbox/src/test/java/org/jclouds/virtualbox/functions/CreateMediumIfNotAlreadyExistsLiveTest.java
index c38c5d7dc0..e9dc309698 100644
--- a/sandbox-apis/virtualbox/src/test/java/org/jclouds/virtualbox/functions/CreateMediumIfNotAlreadyExistsLiveTest.java
+++ b/sandbox-apis/virtualbox/src/test/java/org/jclouds/virtualbox/functions/CreateMediumIfNotAlreadyExistsLiveTest.java
@@ -30,6 +30,8 @@ import org.jclouds.virtualbox.domain.ErrorCode;
 import org.jclouds.virtualbox.domain.HardDisk;
 import org.testng.annotations.Test;
 import org.virtualbox_4_1.DeviceType;
+import org.virtualbox_4_1.IMedium;
+import org.virtualbox_4_1.IProgress;
 import org.virtualbox_4_1.VBoxException;
 
 /**
@@ -41,9 +43,10 @@ public class CreateMediumIfNotAlreadyExistsLiveTest extends BaseVirtualBoxClient
    public void testCreateMedium() throws Exception {
       String path = System.getProperty("user.home") + "/jclouds-virtualbox-test/test-medium-1.vdi";
       HardDisk hardDisk = HardDisk.builder().diskpath(path).controllerPort(0).deviceSlot(0).build();
-      new CreateMediumIfNotAlreadyExists(manager, true).apply(hardDisk);
+      IMedium iMedium = new CreateMediumIfNotAlreadyExists(manager, true).apply(hardDisk);
       manager.getVBox().findMedium(path, DeviceType.HardDisk);
       assertFileCanBeDeleted(path);
+      deleteMediumAndBlockUntilComplete(iMedium);
    }
 
    @Test
@@ -63,10 +66,12 @@ public class CreateMediumIfNotAlreadyExistsLiveTest extends BaseVirtualBoxClient
    public void testCreateSameMediumTwiceWhenUsingOverwrite() throws Exception {
       String path = System.getProperty("user.home") + "/jclouds-virtualbox-test/test-medium-3.vdi";
       HardDisk hardDisk = HardDisk.builder().diskpath(path).controllerPort(0).deviceSlot(0).build();
-      new CreateMediumIfNotAlreadyExists(manager, true).apply(hardDisk);
-      new CreateMediumIfNotAlreadyExists(manager, true).apply(hardDisk);
+      IMedium iMedium = new CreateMediumIfNotAlreadyExists(manager, true).apply(hardDisk);
+      iMedium = new CreateMediumIfNotAlreadyExists(manager, true).apply(hardDisk);
       manager.getVBox().findMedium(path, DeviceType.HardDisk);
       assertFileCanBeDeleted(path);
+      deleteMediumAndBlockUntilComplete(iMedium);
+
    }
 
    private void assertFileCanBeDeleted(String path) {
@@ -74,4 +79,10 @@ public class CreateMediumIfNotAlreadyExistsLiveTest extends BaseVirtualBoxClient
       boolean mediumDeleted = file.delete();
       assertTrue(mediumDeleted);
    }
+   
+   void deleteMediumAndBlockUntilComplete(IMedium medium){
+      final IProgress progress = medium.deleteStorage();
+      progress.waitForCompletion(-1);
+   }
+   
 }