Message type: E = Error
Message class:  FINS_FI_MIG - SAP S/4HANA Finance: Data Migration 
Message number: 003
Message text: No source ledgers for migration of balances defined
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The SAP error message FINS_FI_MIG003 indicates that there are no source ledgers defined for the migration of balances in the Financial Accounting (FI) module. This error typically occurs during the migration process when you are trying to transfer balances from legacy systems to SAP S/4HANA or during the use of the Migration Cockpit.
Cause: Missing Configuration: The source ledgers (such as the General Ledger or other financial ledgers) have not been properly configured in the system. Incorrect Migration Settings: The migration settings may not have been correctly defined, leading to the system not recognizing any source ledgers. Data Transfer Issues: There may be issues with the data transfer from the legacy system, resulting in no ledgers being available for migration. Authorization Issues: The user may not have the necessary authorizations to access the source ledgers.
Solution: Check Configuration: Go to the SAP Customizing Implementation Guide (IMG) and navigate to Financial Accounting (New) > General Ledger Accounting > Migration
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