diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/site/markdown/TransparentEncryption.md b/hadoop-hdfs-project/hadoop-hdfs/src/site/markdown/TransparentEncryption.md
index b82b400a3e3..1a403c66e8d 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/site/markdown/TransparentEncryption.md
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/site/markdown/TransparentEncryption.md
@@ -173,7 +173,7 @@ Create a new encryption zone.
 | | |
 |:---- |:---- |
 | *path* | The path of the encryption zone to create. It must be an empty directory. A trash directory is provisioned under this path.|
-| *keyName* | Name of the key to use for the encryption zone. |
+| *keyName* | Name of the key to use for the encryption zone. Uppercase key names are unsupported. |
 
 ### <a name="listZones"></a>listZones