Unrecognized Guid format.
Guid should contain....
Either of these errors can occur for two reasons:
Invoices were processed and supplier account were allocated before integrating the company with Xero
Invoices were processed and supplier account were allocated while connected to a different accounts package, then switching the company's integration to Xero
To clear either of these errors, you will need to do the following:
Unpublish the affected invoices
Clear the supplier/customer, category, and VAT code dropdown menus
Re-select the codes
Publish the invoices again
Please note: The error message will not clear until the invoices have successfully published through to Xero.