How To Fix ACO400 - Substitutes for '&1' are being changed by &2

SAP Error Message - Details

• Message type: E = Error

• Message class: ACO - Error Messages for Package ACO

• Message number: 400

• Message text: Substitutes for '&1' are being changed by &2

What causes this issue?

You want to enter substitutes for '&V1&', but this data is currently
being changed by &V2&.

System Response

The system does not allow you to enter substitutes for '&V1&'.

How to fix this error?

Try and enter the substitutes for '&V1&' again, later on.

Procedure for System Administrators

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.

Smart SAP Assistant

• What is the cause and solution for SAP error message ACO400 - Substitutes for '&1' are being changed by &2 ?

  The SAP error message ACO400 indicates that there is a conflict or issue with the substitution of a specific item (represented by &1) that is being modified by another item (represented by &2). This typically occurs in the context of material management, where substitutions are used to replace one material with another in various processes, such as sales orders, production orders, or inventory management.
  Cause:
  
  Substitution Configuration: The error may arise from the configuration of substitution rules in the system. If multiple substitution rules are defined for the same material, it can lead to conflicts.
  Data Inconsistency: There may be inconsistencies in the master data for the materials involved, such as incorrect or missing information in the material master records.
  User Actions: The error can also occur if a user attempts to change a substitution while another process is already modifying it.
  
  Solution:
  
  Review Substitution Rules: Check the substitution rules defined in the system for the materials involved. Ensure that there are no conflicting rules and that they are set up correctly.
  Check Material Master Data: Verify the material master data for both the original item (&1) and the substitute item (&2). Ensure that all necessary fields are filled out correctly and that there are no inconsistencies.
  Locking Issues: If the error is due to concurrent modifications, ensure that no other users are currently editing the substitution. You may need to wait for the other process to complete or coordinate with the other user.
  Transaction Logs: Check transaction logs or change documents to see if there are any recent changes that might have caused the issue.
  Consult Documentation: Refer to SAP documentation or help resources for specific guidance on handling substitution errors in your version of SAP.
  
  Related Information:
  
  Transaction Codes: You may need to use transaction codes like MM02 (Change Material), MM03 (Display Material), or OVB1 (Maintain Substitutions) to review and modify substitution settings.
  SAP Notes: Check SAP Notes for any known issues or patches related to this error message. SAP Notes can provide additional context or solutions for specific scenarios.
  Support: If the issue persists after checking the above points, consider reaching out to your SAP support team or consulting with an SAP expert for further assistance.
  
  By following these steps, you should be able to identify the cause of the ACO400 error and implement a solution to resolve it.