Minor fix in naming naming series
diff --git a/erpnext/setup/doctype/naming_series/naming_series.py b/erpnext/setup/doctype/naming_series/naming_series.py
index cb0d437..09a019c 100644
--- a/erpnext/setup/doctype/naming_series/naming_series.py
+++ b/erpnext/setup/doctype/naming_series/naming_series.py
@@ -48,11 +48,10 @@
 		# validate names
 		for i in options: self.validate_series_name(i)
 
-		if self.user_must_always_select:
+		if options and self.user_must_always_select:
 			options = [''] + options
-			default = ''
-		else:
-			default = options[0]
+
+		default = options[0] if options else ''
 
 		# update in property setter
 		prop_dict = {'options': "\n".join(options), 'default': default}