How To Fix CN158 - Reference fields of selected activities are not unique

SAP Error Message - Details

• Message type: E = Error

• Message class: CN - Meldungen für Netzpläne

• Message number: 158

• Message text: Reference fields of selected activities are not unique

What causes this issue?

Network activities were determined for the selection criteria you
entered. At least two activities with the same reference field &V1&
exist:
Network/activity &V2&
Network/activity &V3&

System Response

The reference fields in the selected activities must be unique.

How to fix this error?

Check whether the reference fields in the networks are unique.

Error message extract from SAP system. Copyright SAP SE.

Smart SAP Assistant

• What is the cause and solution for SAP error message CN158 - Reference fields of selected activities are not unique ?

  The SAP error message CN158 ("Reference fields of selected activities are not unique") typically occurs in the context of project management and controlling, particularly when dealing with network activities in SAP Project System (PS). This error indicates that the system has detected a conflict with the reference fields of the selected activities, meaning that the activities you are trying to process or manipulate are not uniquely identifiable based on the reference fields.
  Causes:
  
  Duplicate Activities: There may be multiple activities with the same reference fields (e.g., same WBS element, same network, etc.) that are being selected for processing.
  Incorrect Selection: The user may have selected multiple activities that are not meant to be processed together due to their non-unique reference fields.
  Data Integrity Issues: There could be underlying data integrity issues in the project structure or network that lead to non-unique references.
  
  Solutions:
  
  Check Activity Selection: Review the activities you have selected for processing. Ensure that you are selecting unique activities that do not share the same reference fields.
  Filter Activities: Use filters to narrow down your selection to unique activities. This can help avoid selecting duplicates.
  Review Project Structure: Examine the project structure and network to identify any duplicate activities or inconsistencies in the reference fields.
  Data Correction: If duplicates are found, you may need to correct the data by either renaming or restructuring the activities to ensure uniqueness.
  Consult Documentation: Refer to SAP documentation or help resources for specific guidance on handling project activities and networks.
  
  Related Information:
  
  Transaction Codes: Familiarize yourself with relevant transaction codes in SAP PS, such as CN21 (Create Network), CN22 (Change Network), and CN41 (Display Network).
  SAP Notes: Check for any SAP Notes related to this error message, as they may provide additional insights or patches that address known issues.
  User Roles and Authorizations: Ensure that you have the appropriate authorizations to perform the actions you are attempting, as sometimes authorization issues can lead to unexpected errors.
  
  If the problem persists after trying the above solutions, it may be beneficial to consult with your SAP support team or a functional consultant who specializes in SAP Project System for further assistance.