diff --git a/installers/install_osm.sh b/installers/install_osm.sh
index 77a696e..a425be1 100755
--- a/installers/install_osm.sh
+++ b/installers/install_osm.sh
@@ -135,10 +135,6 @@
             echo "Option -$OPTARG requires an argument" >&2
             usage && exit 1
             ;;
-        \?)
-            echo -e "Invalid option: '-$OPTARG'\n" >&2
-            usage && exit 1
-            ;;
         h)
             usage && exit 0
             ;;