diff --git a/hgdriver/hgdev/hg_scanner.cpp b/hgdriver/hgdev/hg_scanner.cpp
index f79ba11..ee1c902 100644
--- a/hgdriver/hgdev/hg_scanner.cpp
+++ b/hgdriver/hgdev/hg_scanner.cpp
@@ -3374,12 +3374,15 @@ void hg_scanner::erase_option(const char* name)
 }
 void hg_scanner::erase_range(const char* name, const char* opt_name)
 {
-	for (size_t i = 0; i < setting_jsn_.at(name).at("range").size(); i++)
+	if (setting_jsn_.count(name) && setting_jsn_.at(name).count("range") > 0)
 	{
-		if (setting_jsn_.at(name).at("range").at(i) == opt_name)
+		for (size_t i = 0; i < setting_jsn_.at(name).at("range").size(); i++)
 		{
-			setting_jsn_.at(name).at("range").erase(i);
-			break;
+			if (setting_jsn_.at(name).at("range").at(i) == opt_name)
+			{
+				setting_jsn_.at(name).at("range").erase(i);
+				break;
+			}
 		}
 	}
 }