diff --git a/nova/compute/api.py b/nova/compute/api.py
index 6594c29981..12bedf28b6 100644
--- a/nova/compute/api.py
+++ b/nova/compute/api.py
@@ -2907,6 +2907,16 @@ class API(base.Base):
                     LOG.info('Skipping quiescing instance: %(reason)s.',
                              {'reason': err},
                              instance=instance)
+            # NOTE(tasker): discovered that an uncaught exception could occur
+            #               after the instance has been frozen. catch and thaw.
+            except Exception:
+                with excutils.save_and_reraise_exception():
+                    LOG.error("Uncaught exception dusing quiesce of instance",
+                              context=context, instance=instance)
+                    LOG.info("Unquiescing instance to ensure thawed after "
+                             "quiesce failure", instance=instance)
+                    self.compute_rpcapi.unquiesce_instance(context, instance,
+                                                           mapping=None)
 
         @wrap_instance_event(prefix='api')
         def snapshot_instance(self, context, instance, bdms):