diff --git a/src/cfgparse-global.c b/src/cfgparse-global.c
index 540dda79b..f31e7a05a 100644
--- a/src/cfgparse-global.c
+++ b/src/cfgparse-global.c
@@ -591,7 +591,7 @@ int cfg_parse_global(const char *file, int linenum, char **args, int kwm)
 		global.external_check = 1;
 		if (strcmp(args[1], "preserve-env") == 0) {
 			global.external_check = 2;
-		} else {
+		} else if (*args[1]) {
 			ha_alert("parsing [%s:%d] : '%s' only supports 'preserve-env' as an argument, found '%s'.\n", file, linenum, args[0], args[1]);
 			err_code |= ERR_ALERT | ERR_FATAL;
 	                goto out;