maybe it will work now

bin/mpd-monitor

@@ -1,7 +1,14 @@
 #!/bin/sh
 
 # exit if another instance is already running
-if [ -n "$(pidof mpc idleloop)" ]; then
+#if [ !$(pidof mpd-monitor > /dev/null) ]; then
+#  echo "mpd-monitor already running"
+#  exit
+#fi
+
+# this might actually work...
+RUNNING=$(pidof mpc > /dev/null)
+if [ !$RUNNING ]; then
   echo "mpd-monitor already running"
   exit
 fi
@@ -23,7 +30,7 @@ mpc idleloop |
     ARTIST=$(mpc current -f %artist%)
 
     if [ -z "$TITLE" ]; then
-      notify-send "End of queue or queue empty" -i :
+      notify-send "End of queue or queue empty" "or no metadata for track" -i :
     else
       notify-send "$TITLE" "$ARTIST" -i :
     fi