diff --git a/daemon/cluster/swarm.go b/daemon/cluster/swarm.go
index 727612c..9614528 100644
--- a/daemon/cluster/swarm.go
+++ b/daemon/cluster/swarm.go
@@ -33,6 +33,7 @@
 			// API handlers to finish before shutting down the node.
 			c.mu.Lock()
 			if !c.nr.nodeState.IsManager() {
+				c.mu.Unlock()
 				return "", errSwarmNotManager
 			}
 			c.mu.Unlock()