How To Fix AD591 - Table & already changed, 'Add fields' not allowed

AD591 - Overview

• Message type: E = Error

• Message class: AD - Data Dictionary application messages

• Message number: 591

• Message text: Table & already changed, 'Add fields' not allowed

What causes this issue?

The table was already active and already has another revised version
which differs from the active version. Fields from the active version
were changed in the revised version. In this situation the <LS>Append
fields</> function is not allowed.

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?

Use the field maintenance screen of the corresponding table to add
fields to the revised version.

Error message extract from SAP system. Copyright SAP SE.

Smart SAP Assistant

• What is the cause and solution for SAP error message AD591 - Table & already changed, 'Add fields' not allowed ?

  The SAP error message AD591 indicates that you are trying to add fields to a table that has already been changed or modified in a way that prevents further changes. This typically occurs in the context of data dictionary objects in SAP, particularly when working with transparent tables or structures.
  
  Cause:
  
  Table Already Modified: The table you are trying to modify has already been changed in a way that does not allow further modifications, such as adding fields.
  Transport Request Issues: If the table is part of a transport request that has already been released or is in a state that does not allow further changes.
  Table Locking: The table might be locked due to ongoing development or transport activities.
  Development Class Restrictions: The table might belong to a development class that has restrictions on modifications.
  
  
  Solution:
  
  Check Table Status: Verify the status of the table in the Data Dictionary (SE11). If it is marked as "modified,"