Message type: E = Error
Message class:  CNV_OM - Messages for Objectbased Migration 
Message number: 064
Message text: Mass transfer ID &1 already exists in data set
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The SAP error message CNV_OM064 indicates that a mass transfer ID already exists in the dataset you are trying to work with. This error typically occurs during data migration or data transfer processes, particularly when using SAP's data migration tools or during the execution of mass data transfer programs.
Cause: The error is caused by the attempt to create or insert a mass transfer ID that already exists in the system. This can happen due to: Duplicate entries in the source data. An incomplete or interrupted previous data transfer that left behind a mass transfer ID. A configuration issue where the system is not correctly identifying existing entries.
Solution: To resolve this error, you can take the following steps: Check for Existing Mass Transfer IDs: Use transaction codes like SE16 or SE11 to check the relevant database tables (e.g., CNV_MBT_MASS_TRANSFER) for existing mass transfer IDs. Identify if the ID you are trying to create already exists. Remove or Update Existing Entries: If
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