--- a/debian/postinst	Wed Dec 19 22:36:00 2007 +0000
+++ b/debian/postinst	Thu Dec 17 11:30:53 2015 +0000
@@ -21,7 +21,11 @@
 case "$1" in
     configure)
     user=$(getent passwd nagios3 nagios | head -n 1 | cut -f1 -d:)
-    /usr/lib/nagios/plugins/ius/check_exim --init $user
+    if test -z "$user"; then
+	: # trigger for later
+    else
+	/usr/lib/nagios/plugins/ius/check_exim --init $user
+    fi
     ;;
 
     abort-upgrade|abort-remove|abort-deconfigure)