diff --git a/erpnext/patches/v7_2/update_salary_slips.py b/erpnext/patches/v7_2/update_salary_slips.py
index 419d335..b7a4050 100644
--- a/erpnext/patches/v7_2/update_salary_slips.py
+++ b/erpnext/patches/v7_2/update_salary_slips.py
@@ -13,7 +13,9 @@
 				(end_date is null  or end_date = '') and docstatus != 2""", as_dict=True)
 
 	for salary_slip in salary_slips:
-		get_start_end_date = get_month_details(salary_slip.fiscal_year, cint(salary_slip.month) + 1)
+		if not cint(salary_slip.month):
+			continue
+		get_start_end_date = get_month_details(salary_slip.fiscal_year, cint(salary_slip.month))
 		start_date = get_start_end_date['month_start_date']
 		end_date = get_start_end_date['month_end_date']
 		frappe.db.sql("""update `tabSalary Slip` set start_date = %s, end_date = %s where name = %s""",