Migrated Fiscal Years represent data or time periods that predate when CORE became your live accounting system. They are created in two situations: for full historical periods where accounting data exists prior to the company's Go Live Date, for example a Migrated Fiscal Year for 1999 when accounting data exists for December 1999, and as the pre-Go-Live portion of a fiscal year that the Go Live Date falls in the middle of. Check CORE Help Center for details.