Journal Entry is active: Reconciliation posting cannot be used any longer

What causes this issue?

You are going to execute the reconciliation posting CO-FI (Transaction
KALC) despite the Universal Journal Entry is active.

System Response

The reconciliation posting may not be executed any longer, because this
would lead to duplicate entries in the General Ledger:
Postings within CO are posted automatically also in the General Ledger.
There is no need for the reconciliation posting any more.

How to fix this error?

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.