How To Fix CNV_20900012 - Vendor &2 already exists in the system; see long text

CNV_20900012 - Overview

• Message type: E = Error

• Message class: CNV_20900 - Message class for package CNV_20900

• Message number: 012

• Message text: Vendor &2 already exists in the system; see long text

What causes this issue?

Vendor record &V1& is to be renamed to &V2&. Vendor record &V2& exists
in the system, but is not entered as old value in the mapping table.
This would lead to an <DS:TX.CNV_MBT_IMPLICIT_MERGE>implicit merge</>.
This is not allowed.

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

How to fix this error?

If you want to merge &V1& and &V2& to &V2&, enter &V2&, as old value
and as new value in the mapping table and set the priority flag
accordingly. You can set the priority flag either for &V1& or for &V2& .
If you do not want to merge &V1& and &V2&, you can:
Enter a value that does not exist in the master data table for new value
Or
Include &V2& also as old value in the mapping table and enter a
different value for new value.

Error message extract from SAP system. Copyright SAP SE.

CNV_20900012 - Details

• The SAP error message CNV_20900012 indicates that a vendor with the specified identifier (represented by "&2") already exists in the system. This error typically arises during data migration or data upload processes, particularly when using tools like SAP S/4HANA Migration Cockpit or other data transfer methods.
  
  Cause:
  
  
  Duplicate Vendor Entry: The primary cause of this error is that the vendor you are trying to create or import already exists in the system. This can happen if:
  
  The vendor was previously created manually or through another data upload.
  There is a mismatch in the data being imported, leading to an attempt to create a vendor that already exists.
  
  
  
  Data Migration Issues: During data migration, if the source data contains duplicates or if the mapping is incorrect, it can lead to attempts to create existing vendors.
  
  
  
  Solution:
  
  
  Check Existing Vendors: 
  
  Use transaction codes like XK03 (Display Vendor) or MK03 (Display Vendor (Purchasing)) to check if the vendor already exists