diff --git a/shadow.spec b/shadow.spec
index 4a27ccb..565e77f 100644
--- a/shadow.spec
+++ b/shadow.spec
@@ -3,7 +3,7 @@ Summary:       Utilities for managing shadow password files and user/group accou
 Name:          shadow
 Version:       4.5
 Group:         Applications/Security
-Release:       3mamba
+Release:       4mamba
 Vendor:        openmamba
 Distribution:  openmamba
 Packager:      Silvan Calarco <silvan.calarco@mambasoft.it>
@@ -166,32 +166,41 @@ done
 %clean
 [ "%{buildroot}" != / ] && rm -rf %{buildroot}
 
-%post common
-/sbin/ldconfig
+%post
 groupadd shadow -g %{shadowgroupid} 2>/dev/null || :
-exit 0
-
-%preun common
-/sbin/ldconfig
-exit 0
-
-%posttrans common
-if [ -e /etc/shadow.rpmsave ]; then
-   SAVEPWD=`grep "^root:" /etc/shadow.rpmsave | sed "s|root:\([^:]*\):.*|\1|"`
-   NEWPWD=`grep "^root:" /etc/shadow | sed "s|root:\([^:]*\):.*|\1|"`
-   if [ "$NEWPWD" == "" -o "$NEWPWD" == "!" -o "$NEWPWD" == "x" ]; then
-      if [ "$SAVEPWD" != "!" -a "$SAVEPWD" != "" -a "$SAVEPWD" != "x" ]; then
-         mv /etc/shadow.rpmsave /etc/shadow
-      else
-         echo "Unexpected error updating /etc/shadow file: root password was lost, recover needed!"
-      fi
-   fi
+if [ ! -e /etc/shadow ]; then
+   # upgrade/create passwords to shadow system
+   # for a new install or an upgrade
+   /usr/sbin/pwconv
+   chmod 0640 /etc/shadow
+   chgrp shadow /etc/shadow
 fi
-[ -e /etc/shadow ] || touch /etc/shadow
-chmod 0640 /etc/shadow
-chgrp shadow /etc/shadow
 exit 0
 
+#% post common
+#/sbin/ldconfig
+#exit 0
+
+#% preun common
+#/sbin/ldconfig
+#exit 0
+
+#% posttrans common
+#if [ -e /etc/shadow.rpmsave ]; then
+#   SAVEPWD=`grep "^root:" /etc/shadow.rpmsave | sed "s|root:\([^:]*\):.*|\1|"`
+#   NEWPWD=`grep "^root:" /etc/shadow | sed "s|root:\([^:]*\):.*|\1|"`
+#   if [ "$NEWPWD" == "" -o "$NEWPWD" == "!" -o "$NEWPWD" == "x" ]; then
+#      if [ "$SAVEPWD" != "!" -a "$SAVEPWD" != "" -a "$SAVEPWD" != "x" ]; then
+#         mv /etc/shadow.rpmsave /etc/shadow
+#      else
+#         echo "Unexpected error updating /etc/shadow file: root password was lost, recovery needed!"
+#      fi
+#   fi
+#fi
+#chmod 0640 /etc/shadow
+#chgrp shadow /etc/shadow
+#exit 0
+
 %files -f shadow-main.man
 %defattr(-,root,root)
 %{_bindir}/chage
@@ -254,6 +263,9 @@ exit 0
 %{_mandir}/man8/nologin.8*
 
 %changelog
+* Wed Nov 15 2017 Silvan Calarco <silvan.calarco@mambasoft.it> 4.5-4mamba
+- create /etc/shadow with pwconv if not existing in %post
+
 * Thu Nov 09 2017 Silvan Calarco <silvan.calarco@mambasoft.it> 4.5-3mamba
 - create /etc/shadow if missing