How To Fix CN611 - Network contains loops and cannot be scheduled

CN611 - Overview

• Message type: E = Error

• Message class: CN - Meldungen für Netzpläne

• Message number: 611

• Message text: Network contains loops and cannot be scheduled

What causes this issue?

The network cannot be scheduled because there are relationships to
activities which create a loop.

System Response

INCLUDE 'NA_ALLG_NOFUNKTION' OBJECT DOKU ID TX

How to fix this error?

RESET N1
Call up the network structure graphic.
Select the menu options <ZH>Edit -> Functions -> Loop analysis ->
Execute</>.
The relationships which create loops are highlighted.
Choose new relationships between activities so that no loops exist.
Select the menu options <ZH>Edit -> Functions -> Loop analysis ->
Execute</>.
The relationships are no longer highlighted.

Error message extract from SAP system. Copyright SAP SE.

CN611 - Details

• The SAP error message CN611 ("Network contains loops and cannot be scheduled") typically occurs in the context of project management within SAP, particularly when dealing with networks in the Project System (PS) module. This error indicates that there is a circular dependency in the network activities, which prevents the system from scheduling the project correctly.
  
  Cause:
  
  Circular Dependencies: The most common cause of this error is the presence of circular dependencies among activities in the network. This means that one or more activities are interlinked in such a way that they create a loop, making it impossible for the scheduling algorithm to determine a valid sequence of execution.
  Incorrect Relationships: Incorrectly defined relationships (predecessors and successors) between activities can lead to loops. For example, if Activity A is a predecessor of Activity B, and Activity B is also a predecessor of Activity A, this creates a loop.
  Multiple Paths: If there are multiple paths