How To Fix CN601 - No loop in the network

SAP Error Message - Details

• Message type: E = Error

• Message class: CN - Meldungen für Netzpläne

• Message number: 601

• Message text: No loop in the network

Self-Explanatory Message

Since SAP believes that this specific error message is 'self-explanatory,' no more information has been given.The majority of messages in the SAP system have a message text, however this is frequently insufficient to comprehend or resolve the problem.

To make things easier, more detailed information is frequently added to describe the issue, how to fix it, and the necessary steps or configuration modifications.

Unfortunately, there isn't any extra information in this error notice.

What else can you do?

First, use our AnswerBot below to get a possible cause and solution (requires a premium subscription).

Also, review the in-depth Common Questions & Answers listed below; you could discover a solution there or be able to connect with others who have faced similar challenges.

You can also try searching the SAP support portal (support.sap.com) but you need a special user ID to access it. It is possible that an SAP support note exists that provides additional details about the mistake or even steps for fixing it.

Smart SAP Assistant

• What is the cause and solution for SAP error message CN601 - No loop in the network ?

  The SAP error message CN601 "No loop in the network" typically occurs in the context of project management and network planning within the SAP system, particularly when dealing with network activities in Project System (PS) or Production Planning (PP). This error indicates that the system has detected a situation where a network activity is not properly linked, leading to a lack of a valid loop or sequence in the network structure.
  Cause:
  
  Incorrect Network Structure: The network may not have been set up correctly, leading to missing dependencies or relationships between activities.
  Missing Relationships: There may be missing predecessor or successor relationships between activities, which are necessary for the network to function correctly.
  Improper Activity Configuration: Activities may not be configured properly, leading to inconsistencies in the network.
  Circular Dependencies: The system may detect a circular dependency that prevents it from establishing a valid sequence of activities.
  
  Solution:
  
  Check Network Structure: Review the network structure to ensure that all activities are properly linked. Make sure that each activity has the necessary predecessor and successor relationships.
  Define Relationships: If any relationships are missing, define them using the appropriate transaction codes (e.g., CN21 for creating networks, CN22 for changing networks).
  Review Activity Configuration: Ensure that each activity is configured correctly, including start and finish dates, durations, and any other relevant parameters.
  Use Network Planning Tools: Utilize SAP's network planning tools to visualize the network and identify any issues with the structure.
  Consult Documentation: Refer to SAP documentation or help resources for guidance on setting up networks and resolving common issues.
  
  Related Information:
  
  Transaction Codes: Familiarize yourself with relevant transaction codes such as CN21 (Create Network), CN22 (Change Network), and CN41 (Display Network).
  SAP Notes: Check SAP Notes for any known issues or patches related to the CN601 error.
  Training and Documentation: Consider training resources or documentation specific to SAP Project System or Production Planning for a deeper understanding of network management.
  
  If the issue persists after following these steps, it may be beneficial to consult with an SAP expert or your organization's SAP support team for further assistance.