diff --git a/appimage/build_appimage.sh b/appimage/build_appimage.sh
index 849face15..8f9f6b32a 100755
--- a/appimage/build_appimage.sh
+++ b/appimage/build_appimage.sh
@@ -309,6 +309,9 @@ case "$1" in
       missing_argument "$1"
     fi
     ;;
+  -*)
+	echo "Error: Unsupported parameter $1" >&2
+	exit 1
   esac
 done