How To Fix TG551 - Program already active (ENQUEUE pending)

SAP Error Message - Details

• Message type: E = Error

• Message class: TG - Messages for Upgrade Repository Switch

• Message number: 551

• Message text: Program already active (ENQUEUE pending)

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.

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Smart SAP Assistant

• What is the cause and solution for SAP error message TG551 - Program already active (ENQUEUE pending) ?

  The SAP error message TG551 ("Program already active (ENQUEUE pending)") typically occurs when a user attempts to start a program that is already running in the background or is locked due to an enqueue lock. This can happen in various scenarios, such as when a job is scheduled to run, or when a user tries to execute a report that is already being processed.
  Cause:
  
  Program Already Running: The program or report you are trying to execute is already active in the system.
  Enqueue Lock: The program has an enqueue lock that prevents it from being executed again until the current instance finishes or the lock is released.
  Long-Running Jobs: If the program takes a long time to execute, it may still be running when you try to start it again.
  System Configuration: There may be system settings or configurations that limit the number of concurrent executions of a program.
  
  Solution:
  
  Check Active Jobs: Use transaction codes like SM37 (Job Monitoring) to check if the program is currently running. Look for jobs with the same name and see their status.
  Wait for Completion: If the program is running, you may need to wait for it to complete before trying to execute it again.
  Terminate the Job: If the job is stuck or taking too long, you can terminate it using SM37 by selecting the job and choosing the option to cancel it.
  Check for Locks: Use transaction SM12 to check for any locks related to the program. If you find any locks that are no longer needed, you can delete them (ensure you have the necessary authorizations and that it is safe to do so).
  Review Program Logic: If this issue occurs frequently, review the program logic to ensure it handles concurrent executions properly, or consider implementing a mechanism to prevent multiple instances from running simultaneously.
  Consult Basis Team: If you are unable to resolve the issue, consult your SAP Basis team for further assistance. They can provide insights into system performance and configuration.
  
  Related Information:
  
  Transaction Codes:
  
  SM37: Job Monitoring
  SM12: Lock Entries
  SM21: System Log
  
  
  SAP Notes: Check SAP Notes for any known issues or patches related to the specific program or transaction you are working with.
  Documentation: Review the documentation for the specific program to understand its expected behavior and any limitations regarding concurrent executions.
  
  By following these steps, you should be able to diagnose and resolve the TG551 error in SAP.