Dont update series starts from if no prefix
diff --git a/erpnext/setup/doctype/naming_series/naming_series.py b/erpnext/setup/doctype/naming_series/naming_series.py
index 4b7e741..2ad1236 100644
--- a/erpnext/setup/doctype/naming_series/naming_series.py
+++ b/erpnext/setup/doctype/naming_series/naming_series.py
@@ -89,3 +89,5 @@
 			else:
 				sql("insert into tabSeries (name, current) values (%s,%s)",(cstr(self.doc.prefix),cint(self.doc.starts_from)-1))
 			msgprint("Series Updated Successfully")
+		else:
+			msgprint("Please select prefix first")