diff --git a/x-pack/plugin/security/src/main/java/org/elasticsearch/xpack/security/support/SecurityIndexManager.java b/x-pack/plugin/security/src/main/java/org/elasticsearch/xpack/security/support/SecurityIndexManager.java
index 048dd2fd7a925..1de6ce7eed4fd 100644
--- a/x-pack/plugin/security/src/main/java/org/elasticsearch/xpack/security/support/SecurityIndexManager.java
+++ b/x-pack/plugin/security/src/main/java/org/elasticsearch/xpack/security/support/SecurityIndexManager.java
@@ -137,7 +137,7 @@ public ElasticsearchException getUnavailableReason() {
         } else if (state.indexExists()) {
             return new UnavailableShardsException(
                 null,
-                "at least one primary shard for the index [" + state.concreteIndexName + "] is unavailable"
+                "index [" + state.concreteIndexName + "] exists but at least one shard is unavailable"
             );
         } else {
             return new IndexNotFoundException(state.concreteIndexName);