If you voided a check written to an occasional vendor and wish to void the invoice, follow these steps:
1.Go to System/Hide Deleted Accounts. If necessary, click on this so it is NOT checked.
2.Go to Payables/Configure/Vendors
3.Select the vendor.
4.Click on Undelete in the right pane and save.
5.You can now access the vendor in Invoice Updates, Vendor Invoices, etc. Note that this vendor is no longer an Occasional Vendor. The steps taken changed it to a regular vendor.
6. Run the "Payables/Void/Update Invoices" command and select the Vendor and Invoice you wish to void.