Dear All,It will be stupid to go to user exit for this problem.Costing and cost release of a material to be must is a standard scenario and SAP it self provides the solution for this.Status CSER is set for any costing errors and doesnot permit any further functionalitties in order.To check you need to Run function - >cost in order to check costing of material.Same can be automatically be fired by customizing of order type parameters -- Costing on saving / release of order.Maitenance of material status is a good idea for blocking of production related activities and in fact is used for blocking of outdated materials.User exit is a solution for non provided / non standard / custom checks and activities and is used for many other purposes. In fact variance key checking in user exit is fantastic. Regards,Aks