diff --git a/pandora_agents/unix/ChangeLog b/pandora_agents/unix/ChangeLog
index 0157a97e8b..3a4d09cdd4 100644
--- a/pandora_agents/unix/ChangeLog
+++ b/pandora_agents/unix/ChangeLog
@@ -1,3 +1,8 @@
+2012-06-21  Koichiro Kikuchi <koichiro@rworks.jp>
+
+	* pandora_agent.redhat.spec: Merged from 4.0 branch. Don't create
+	 pandora user if already exists.
+
 2012-05-30  Ramon Novoa  <rnovoa@artica.es>
 
 	* pandora_agent: Merged from 4.0 branch. Check for valid regular
diff --git a/pandora_agents/unix/pandora_agent.redhat.spec b/pandora_agents/unix/pandora_agent.redhat.spec
index 8cbdcaed77..0ed6c2fcef 100755
--- a/pandora_agents/unix/pandora_agent.redhat.spec
+++ b/pandora_agents/unix/pandora_agent.redhat.spec
@@ -66,10 +66,10 @@ fi
 rm -Rf $RPM_BUILD_ROOT
 
 %pre
-/usr/sbin/useradd -d %{prefix}/pandora -s /bin/false -M -g 0 pandora
+getent passwd pandora >/dev/null || \
+	/usr/sbin/useradd -d %{prefix}/pandora -s /bin/false -M -g 0 pandora
 exit 0
 
-
 %post
 if [ ! -d /etc/pandora ] ; then
 	mkdir -p /etc/pandora