3487682 - Error "You can't make currency type changes; postings exist in company code *" in SSCUI 103379

Error "You can't make currency type changes; postings exist in company code *" occurs in SSCUI 103379 - Define Currency Settings for Ledgers and Company Codes,

when changing Functional Currency for specific company code.

SAP S/4HANA Cloud.

1. Define new currency type **
2. Maintain the global or company code specific conversion settings for the new currency type
3. Define this currency type as 'Free defined currency type' for the combination of ledgers and company codes
4. Define this currency type as Functional Currency for relevant company code

The error occurs not because of the changing of functional currency but because a new currency type was configured for the company code.

It is not possible to add a currency type to a company code if there are already postings because all existing data in table BSEG and ACDOCA will be incomplete, this will cause severe inconsistency in systems. Thus the message cannot be configured in this situation.

Note that the definition of currency types for company codes is a fundamental configuration and must be done carefully at the very beginning. Once postings are made with the currency configuration, it is not possible to add, change or delete currency types anymore.

The functional currency is not an additional currency type but it is reusing an existing currency type. Therefore the functional currency could be changed though there are postings. But after a change of the functional currency all postings must be corrected. For specific postings e.g. from Advanced Foreign Currency Valuation the migration report for functional currency is not able to correct the journal entry completely. That's why a change of a functional currency is  a risk.

See https://help.sap.com/docs/SAP_S4HANA_CLOUD/0fa84c9d9c634132b7c4abb9ffdd8f06/73c10be5deac49c993956ab3281c9ea1.html?locale=en-US

103379, Define Currency Settings for Ledgers and Company Codes, functional currency, "You can't make currency type changes; postings exist in company code *". , KBA , FI-GL-GL-G-2CL , Closing Operations / Period-End (Public Cloud) , Problem

SAP S/4HANA Cloud Public Edition all versions ; SAP S/4HANA Cloud all versions