diff --git a/lib/emuctl/z80.bat b/lib/emuctl/z80.bat
index 0bb400f..b195239 100644
--- a/lib/emuctl/z80.bat
+++ b/lib/emuctl/z80.bat
@@ -16,3 +16,4 @@ IFF 11 == %1
 ENDIFF
 echo 'Select openMSX Z80 emulation speed'
 echo 'Usage: z80 <3/7/11>'
+exit 1