How To Fix CN136 - Specified assignment to WBS element already exists

SAP Error Message - Details

• Message type: E = Error

• Message class: CN - Meldungen für Netzpläne

• Message number: 136

• Message text: Specified assignment to WBS element already exists

Self-Explanatory Message

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Smart SAP Assistant

• What is the cause and solution for SAP error message CN136 - Specified assignment to WBS element already exists ?

  The SAP error message CN136 ("Specified assignment to WBS element already exists") typically occurs when you attempt to assign a cost element, activity, or other resource to a Work Breakdown Structure (WBS) element that already has an existing assignment for that specific resource or cost element. This is a common issue in project management within SAP, particularly when dealing with project planning and budgeting.
  Cause:
  
  Duplicate Assignment: The most common cause is that the resource or cost element you are trying to assign to the WBS element has already been assigned.
  Incorrect Data Entry: There may be a mistake in the data entry, such as trying to assign the same cost element or activity multiple times.
  Project Structure: The project structure may not allow for multiple assignments of the same resource to a single WBS element.
  
  Solution:
  
  Check Existing Assignments: Review the existing assignments for the WBS element to confirm if the resource or cost element is already assigned. You can do this by navigating to the WBS element in the project structure and checking the assignments.
  Modify Existing Assignment: If the assignment already exists and you need to change it, consider modifying the existing assignment instead of creating a new one.
  Remove Duplicate Assignment: If the assignment is indeed a duplicate and not needed, you can remove the existing assignment before trying to add the new one.
  Use Different Resource/Cost Element: If you need to assign a different resource or cost element, ensure that it is not already assigned to the WBS element.
  Consult Documentation: Refer to SAP documentation or your organization's guidelines for managing WBS assignments to ensure compliance with project management practices.
  
  Related Information:
  
  Transaction Codes: You may use transaction codes like CJ20N (Project Builder) or CJ02 (Change WBS Element) to view and manage WBS assignments.
  SAP Notes: Check SAP Notes for any known issues or patches related to this error message.
  User Authorization: Ensure that you have the necessary authorizations to make changes to the WBS elements and their assignments.
  Training and Support: If you are unsure about the process, consider reaching out to your SAP support team or attending training sessions on project management in SAP.
  
  By following these steps, you should be able to resolve the CN136 error and manage your WBS assignments effectively.