How To Fix CN603 - Network contains & loop(s)

SAP Error Message - Details

• Message type: E = Error

• Message class: CN - Meldungen für Netzpläne

• Message number: 603

• Message text: Network contains & loop(s)

Self-Explanatory Message

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Smart SAP Assistant

• What is the cause and solution for SAP error message CN603 - Network contains & loop(s) ?

  The SAP error message CN603 ("Network contains & loop(s)") typically occurs in the context of project management and network planning within SAP, particularly when dealing with networks in the Project System (PS) module. This error indicates that there is a loop in the network structure, which can prevent the system from processing the network correctly.
  Cause:
  The error is caused by the presence of circular dependencies in the network. This means that one or more activities in the network are incorrectly linked, creating a situation where the system cannot determine a clear path for execution. This can happen due to:
  
  Incorrectly Defined Relationships: Activities may have been linked in such a way that they point back to themselves or create a cycle.
  Manual Changes: Manual adjustments to the network structure that inadvertently create loops.
  Data Migration Issues: If data has been migrated from another system, it may have introduced inconsistencies or loops.
  
  Solution:
  To resolve the CN603 error, you can follow these steps:
  
  
  Analyze the Network Structure:
  
  Use transaction codes like CN41 (Network Overview) or CN42 (Network Activity Overview) to visualize the network and identify the problematic activities.
  Check the relationships (dependencies) between activities to find any circular references.
  
  
  
  Correct the Relationships:
  
  Once you identify the activities involved in the loop, you will need to adjust the relationships. This may involve deleting or modifying the links between activities to ensure a linear flow without cycles.
  Ensure that each activity has a clear predecessor and successor without returning to a previous activity.
  
  
  
  Use the Network Check Functionality:
  
  SAP provides a network check function that can help identify issues within the network. You can use transaction CN22 (Change Network) and then execute the check to find and resolve any inconsistencies.
  
  
  
  Recreate the Network:
  
  If the network is too complex or if the loops are difficult to untangle, consider recreating the network from scratch, ensuring that you define the relationships correctly from the beginning.
  
  
  
  Consult Documentation:
  
  Refer to SAP documentation or help resources for specific guidance on network structures and relationships in the Project System.
  
  
  
  Related Information:
  
  Transaction Codes: Familiarize yourself with relevant transaction codes such as CN01 (Create Network), CN02 (Change Network), and CN03 (Display Network).
  SAP Notes: Check SAP Notes for any known issues or patches related to network processing in your version of SAP.
  Training and Support: If you are unsure about how to proceed, consider reaching out to your SAP support team or consulting with an SAP expert who specializes in the Project System module.
  
  By following these steps, you should be able to identify and resolve the CN603 error effectively.