Message type: E = Error
Message class:  FAGL_MIG - Migration to New General Ledger Accounting 
Message number: 049
Message text: Changes are NOT applied because assignments already exist
You are trying to change either a migration plan for which migration has
already started or a migration plan that already has company codes and
ledgers assigned to it. This is <ZH>not </>allowed.
Your changes are <ZH>not </>saved.
If the migration has <ZH>not yet</> started for this migration plan,
first remove the assignment of the company code and ledger.
The system issues an error message and will not allow you to continue with this transaction until the error is resolved.
Error message extract from SAP system. Copyright SAP SE.
The SAP error message FAGL_MIG049 indicates that changes you are trying to apply in the context of the migration of General Ledger (G/L) accounts are not being applied because there are existing assignments that conflict with the changes. This typically occurs during the migration process from classic G/L to the new G/L or when making changes to account assignments in the G/L.
Cause: Existing Assignments: The error usually arises when there are already existing assignments for the accounts you are trying to modify. This could be due to prior configurations or data that have been set up in the system. Data Integrity Issues: The system is designed to prevent changes that could lead to inconsistencies in financial reporting or data integrity. Migration Process: If you are in the process of migrating data, the system may have restrictions in place to ensure that existing data is not overwritten or corrupted.
Solution: Review Existing Assignments: Check the existing
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