Tax Australian: Error 'Given ExtRef GUID __ is already present in this document class under Class Document URI'

The error 'Given ExtRef GUID ----- is already present in this document class under Class Document URI' may occur in an Individual tax return when saving/exiting the tax return. The Tax return is then locked afterwards.

To resolve this issue a script needs to be run. Please raise a new case online and reference the title of this article so our support team can assist you.