Hi Dil

I'm not sure which version you're on but in the Invoice Address tab you should see the Approval Status. If it is anything other than Not Required then this could the cause of your problem. One way around it would be to temporarily remove the approval rules for purchase invoices, do some kind of update on one of these purchase invoices - even if it doesn't let you change a field, it should change the window status to "Update", then press Save, and see if the approval status changes back to Not Required. If this works, do the same for the other purchase invoices. Once finished, reinstate the approval rules.

Regards

Paul