How To Fix REEXAA100 - RE Classic not allowed to be active together with FI-AA (new)

REEXAA100 - Overview

• Message type: E = Error

• Message class: REEXAA - External Messages: Asset Accounting

• Message number: 100

• Message text: RE Classic not allowed to be active together with FI-AA (new)

What causes this issue?

You have activated the <LS>FI-AA, Parallel Valuation</> (<AB>
FIN_AA_PARALLEL_VAL</>) business function and the relevant Customizing
switch for Asset Accounting (new).
Deactivating <LS>Flexible Real Estate Management (RE-FX)</> would
automatically activate Classic RE. Classic RE, however, must <ZH>not</>
be activated together with Asset Accounting (new).

System Response

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

How to fix this error?

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.

Smart SAP Assistant

• What is the cause and solution for SAP error message REEXAA100 - RE Classic not allowed to be active together with FI-AA (new) ?

  The SAP error message REEXAA100 indicates that there is a conflict between the Real Estate (RE) module and the Asset Accounting (FI-AA) module in SAP. Specifically, it states that the "RE Classic" functionality cannot be active simultaneously with the "FI-AA (new)" functionality. This is a common issue when transitioning from older versions of SAP to newer ones, particularly when dealing with the integration of different modules.
  
  Cause:
  The error occurs because the system is configured to use both the classic Real Estate (RE Classic) and the new Asset Accounting (FI-AA) functionalities, which are not compatible with each other. This typically happens when:
  
  The system is in the process of upgrading or migrating from an older version of SAP to a newer one.
  There are configuration settings that have not been updated to reflect the new functionalities.
  The system is trying to use both functionalities for the same business processes, which leads to conflicts.
  
  
  Solution:
  To resolve this