diff --git a/nova/tests/unit/virt/xenapi/test_vmops.py b/nova/tests/unit/virt/xenapi/test_vmops.py
index 624a6fcf9cec..a4777cc8a4f8 100644
--- a/nova/tests/unit/virt/xenapi/test_vmops.py
+++ b/nova/tests/unit/virt/xenapi/test_vmops.py
@@ -2100,8 +2100,10 @@ class AttachInterfaceTestCase(VMOpsTestBase):
         self.vmops.vif_driver.unplug.assert_called_once_with(
             self.fake_instance, self.fake_vif, 'fake_vm_ref')
 
+    @mock.patch('nova.virt.xenapi.vmops.LOG.exception')
     @mock.patch.object(vmops.VMOps, '_get_vm_opaque_ref')
-    def test_detach_interface_exception(self, mock_get_vm_opaque_ref):
+    def test_detach_interface_exception(self, mock_get_vm_opaque_ref,
+                                        mock_log_exception):
         mock_get_vm_opaque_ref.return_value = 'fake_vm_ref'
         self.vmops.vif_driver.unplug.side_effect =\
             exception.VirtualInterfaceUnplugException('Failed to unplug VIF')
@@ -2109,3 +2111,15 @@ class AttachInterfaceTestCase(VMOpsTestBase):
         self.assertRaises(exception.VirtualInterfaceUnplugException,
                           self.vmops.detach_interface,
                           self.fake_instance, self.fake_vif)
+        mock_log_exception.assert_called()
+
+    @mock.patch('nova.virt.xenapi.vmops.LOG.exception',
+                new_callable=mock.NonCallableMock)
+    @mock.patch.object(vmops.VMOps, '_get_vm_opaque_ref',
+                       side_effect=exception.InstanceNotFound(
+                           instance_id='fake_vm_ref'))
+    def test_detach_interface_instance_not_found(
+            self, mock_get_vm_opaque_ref, mock_log_exception):
+        self.assertRaises(exception.InstanceNotFound,
+                          self.vmops.detach_interface,
+                          self.fake_instance, self.fake_vif)
diff --git a/nova/virt/xenapi/vmops.py b/nova/virt/xenapi/vmops.py
index 3d0a4e9af6bd..41fc6584cb42 100644
--- a/nova/virt/xenapi/vmops.py
+++ b/nova/virt/xenapi/vmops.py
@@ -2695,6 +2695,10 @@ class VMOps(object):
         try:
             vm_ref = self._get_vm_opaque_ref(instance)
             self.vif_driver.unplug(instance, vif, vm_ref)
+        except exception.InstanceNotFound:
+            # Let this go up to the compute manager which will log a message
+            # for it.
+            raise
         except exception.NovaException:
             with excutils.save_and_reraise_exception():
                 LOG.exception(_('detach network interface %s failed.'),