diff --git a/vm-start.sh b/vm-start.sh
index 8bb4835..88fa138 100755
--- a/vm-start.sh
+++ b/vm-start.sh
@@ -354,6 +354,7 @@ case "$2" in
             CREATE "${INSTALLATION_DISK_LOCATION}"
         else
             echo "Error, no image defined." >&2
+            echo "use --create_disk=<loc_disk>" >&2
         fi
         ;;
     "suppr")