How To Fix CNV_20800233 - Old/New customer number existence and Implicit merge check:

SAP Error Message - Details

• Message type: E = Error

• Message class: CNV_20800 - Message class for CNV_20800

• Message number: 233

• Message text: Old/New customer number existence and Implicit merge check:

What causes this issue?

Existence Check:
All the customer numbers (old value) which are maintained in the mapping
should exist in the table KNA1, otherwise will result in error message.
Also, the maintained new customer numbers should not exist in master
table KNA1, if exists then you can see a warning message.
Implicit Merge:
If old customer number is mapped to an already existing customer number.
For example: If A >B and B already exists
If you want to convert customer number A->B and B already exists in the
table KNA1, then:
In a 1:1 conversion, this is not allowed that source is changed into
target and target itself is not getting changed: Error message.
In an N: 1 conversion, you should check if you want the existing
customer record to be overwritten: Warning message.

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?

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_20800233 - Old/New customer number existence and Implicit merge check: ?

  The SAP error message CNV_20800233 typically occurs during data migration or conversion processes, particularly when using the SAP Customer Migration tool. This error indicates that there is a conflict between old and new customer numbers, specifically that both the old and new customer numbers exist in the system, which can lead to data integrity issues.
  Cause:
  
  Duplicate Customer Numbers: The error arises when the system detects that both the old customer number (from legacy data) and the new customer number (to be used in the SAP system) are present in the database. This can happen if the migration process attempts to create a new customer record that conflicts with an existing one.
  Implicit Merge Check: The system performs an implicit merge check to ensure that there are no conflicts between the old and new customer numbers. If it finds that both numbers exist, it raises this error.
  
  Solution:
  
  Identify Duplicates: Check the customer master data in the SAP system to identify if the old customer number already exists. You can use transaction codes like XD03 (Display Customer) or SE16 (Data Browser) to look up customer records.
  Data Cleansing: If duplicates are found, you may need to cleanse your data. This could involve:
  
  Merging customer records if they represent the same entity.
  Deleting or archiving old customer records that are no longer needed.
  
  
  Adjust Migration Mapping: Review the mapping of old to new customer numbers in your migration tool. Ensure that the mapping does not create conflicts.
  Use Unique Customer Numbers: Ensure that the new customer numbers being created during the migration process are unique and do not conflict with existing records.
  Consult Documentation: Refer to the SAP documentation for the specific migration tool you are using, as it may provide additional guidance on handling such errors.
  
  Related Information:
  
  Transaction Codes: Familiarize yourself with relevant transaction codes such as XD01 (Create Customer), XD02 (Change Customer), and XD03 (Display Customer) for managing customer data.
  SAP Notes: Check SAP Notes for any known issues or patches related to the migration tool you are using. This can provide insights into similar issues faced by other users.
  Data Migration Best Practices: Follow best practices for data migration, including thorough testing in a development or sandbox environment before executing in production.
  
  If the issue persists after following these steps, consider reaching out to SAP support or consulting with an SAP expert for further assistance.