If the .net Framework is not up-to-date, AccountEdge on Windows platforms will return a TC 1231 (TC1231, Termination Code 1231) when attempting to Process Payroll.

The resolution is to install ALL Windows updates, which will update the .NET Framework. Having the latest, up-to-date .NET Framework will resolve the problem.

After installing the Windows Updates you should uninstall and then reinstall AccountEdge.