How To Fix CNV20201420 - Duplicates for &1: target value=&2

SAP Error Message - Details

• Message type: E = Error

• Message class: CNV20201 -

• Message number: 420

• Message text: Duplicates for &1: target value=&2

What causes this issue?

Duplicates: &V1&
Target object =
&V2&
Source object1 =
&V3&
Source object2 =
&V4&
The conversion logic leads to duplicates (for example for asset numbers
or document numbers). However these objects must remain unique and
cannot be merged.

System Response

Error

How to fix this error?

You need to change the conversion logic so that no duplicates occur.
Having done so, execute the activity 'Number range objects: Simulate
conversion' once again.

Procedure for System Administrators

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

Error message extract from SAP system. Copyright SAP SE.

Smart SAP Assistant

• What is the cause and solution for SAP error message CNV20201420 - Duplicates for &1: target value=&2 ?

  The SAP error message CNV20201420, which indicates "Duplicates for &1: target value=&2," typically arises during data migration or conversion processes, particularly when using SAP's Data Migration tools or during the execution of the SAP S/4HANA Migration Cockpit. This error suggests that there are duplicate entries in the data being processed, which violates the uniqueness constraints defined in the target system.
  Cause:
  
  
  Duplicate Data: The primary cause of this error is the presence of duplicate records in the source data that are being migrated to the target system. This could be due to:
  
  Multiple records in the source system that have the same key or identifier.
  Data extraction processes that inadvertently pull in duplicate entries.
  Incorrect data preparation or cleansing prior to migration.
  
  
  
  Unique Constraints: The target system may have unique constraints defined for certain fields (e.g., primary keys, unique indexes) that the incoming data must adhere to. If the data being migrated contains duplicates for these fields, the error will occur.
  
  
  Solution:
  
  
  Identify Duplicates: 
  
  Review the source data to identify the duplicates. You can use SQL queries or data analysis tools to find records with the same key or identifier.
  For example, if you are migrating customer data, check for customers with the same customer ID or name.
  
  
  
  Data Cleansing:
  
  Remove or consolidate duplicate records in the source data. This may involve:
  
  Merging records that represent the same entity.
  Deleting unnecessary duplicates.
  Ensuring that each record has a unique identifier.
  
  
  
  
  
  Adjust Migration Mapping:
  
  If applicable, adjust the mapping in the migration tool to handle duplicates appropriately. This may involve changing how records are identified or merged during the migration process.
  
  
  
  Test Migration:
  
  After cleansing the data, perform a test migration to ensure that the error does not occur again. Monitor the logs for any other potential issues.
  
  
  
  Consult Documentation: 
  
  Review SAP documentation related to the specific migration tool you are using (e.g., SAP S/4HANA Migration Cockpit) for any additional guidelines or best practices regarding data uniqueness.
  
  
  
  Related Information:
  
  SAP Notes: Check for any relevant SAP Notes that may provide additional insights or solutions related to this error message.
  Data Migration Best Practices: Familiarize yourself with best practices for data migration, including data profiling, cleansing, and validation techniques.
  SAP Community: Engage with the SAP Community forums to see if other users have encountered similar issues and what solutions they have implemented.
  
  By addressing the root cause of the duplicates and ensuring that the data adheres to the target system's constraints, you should be able to resolve the CNV20201420 error and successfully complete the migration process.