diff --git a/CHANGES.txt b/CHANGES.txt
index c95493386a..1fe8d21a12 100644
--- a/CHANGES.txt
+++ b/CHANGES.txt
@@ -38,6 +38,8 @@ Trunk (unreleased changes)
 
     HADOOP-6366. Reduce ivy console output to ovservable level (cos)
 
+    HADOOP-6400. Log errors getting Unix UGI. (Todd Lipcon via tomwhite)
+
   OPTIMIZATIONS
 
   BUG FIXES
diff --git a/src/java/org/apache/hadoop/security/UnixUserGroupInformation.java b/src/java/org/apache/hadoop/security/UnixUserGroupInformation.java
index 62cbb65986..dcb13b90ef 100644
--- a/src/java/org/apache/hadoop/security/UnixUserGroupInformation.java
+++ b/src/java/org/apache/hadoop/security/UnixUserGroupInformation.java
@@ -244,6 +244,7 @@ public class UnixUserGroupInformation extends UserGroupInformation {
       try {
         userName =  getUnixUserName();
       } catch (Exception e) {
+        LOG.warn("Couldn't get unix username, using " + DEFAULT_USERNAME, e);
         userName = DEFAULT_USERNAME;
       }
 
@@ -263,6 +264,7 @@ public class UnixUserGroupInformation extends UserGroupInformation {
       try {
         groupNames = getUnixGroups();
       } catch (Exception e) {
+        LOG.warn("Couldn't get unix groups, using " + DEFAULT_GROUP, e);
         groupNames = new String[1];
         groupNames[0] = DEFAULT_GROUP;
       }