How To Fix CNV_10100257 - New set name &1 for set &2 &3 &4 already exists in target sub class

SAP Error Message - Details

• Message type: E = Error

• Message class: CNV_10100 - Messages from package 10100

• Message number: 257

• Message text: New set name &1 for set &2 &3 &4 already exists in target sub class

What causes this issue?

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

System Response

How to fix this error?

Assign a new unique set name.

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.

Smart SAP Assistant

• What is the cause and solution for SAP error message CNV_10100257 - New set name &1 for set &2 &3 &4 already exists in target sub class ?

  The SAP error message CNV_10100257 typically occurs during data migration or conversion processes, particularly when using the SAP S/4HANA Migration Cockpit or similar tools. This error indicates that there is an attempt to create a new set name in the target subclass that already exists, leading to a conflict.
  Cause:
  The error is caused by the following scenarios:
  
  Duplicate Set Names: The target system already contains a set with the same name that you are trying to create. This can happen if the migration process is being run multiple times or if there are overlapping data sets.
  Incorrect Mapping: There may be an issue with the mapping of data from the source to the target, leading to attempts to create duplicate entries.
  Data Consistency Issues: If the data in the source system is not consistent or has duplicates, it can lead to conflicts during the migration.
  
  Solution:
  To resolve this error, you can take the following steps:
  
  
  Check Existing Sets: Verify if the set name you are trying to create already exists in the target system. You can do this by checking the relevant tables or using transaction codes that allow you to view existing sets.
  
  
  Modify Set Names: If duplicates are found, consider modifying the set name in your migration data to ensure uniqueness. This may involve changing the naming convention or appending a unique identifier.
  
  
  Review Mapping and Data: Ensure that the mapping of data from the source to the target is correct. Check for any inconsistencies or duplicates in the source data that may lead to this error.
  
  
  Run Migration in Smaller Batches: If you are migrating a large volume of data, consider breaking it down into smaller batches to isolate the issue and make it easier to identify duplicates.
  
  
  Consult Documentation: Refer to the SAP documentation related to the specific migration tool you are using for any additional guidelines or troubleshooting steps.
  
  
  Contact SAP Support: If the issue persists after trying the above solutions, consider reaching out to SAP support for further assistance. They may provide insights specific to your system configuration and migration scenario.
  
  
  Related Information:
  
  Transaction Codes: Familiarize yourself with relevant transaction codes such as SE11 (Data Dictionary), SE16 (Data Browser), or specific migration cockpit transactions.
  SAP Notes: Check for any SAP Notes related to the migration tool you are using, as they may contain fixes or workarounds for known issues.
  Migration Cockpit: If you are using the SAP S/4HANA Migration Cockpit, review the migration guide for best practices and common pitfalls.
  
  By following these steps, you should be able to identify the cause of the error and implement a solution to resolve it.