Message type: E = Error
Message class:  CNV_MBT - PCL message class 
Message number: 495
Message text: Deletion technique for table & can't be changed.Deletion already finished
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The SAP error message CNV_MBT495 indicates that there is an issue related to the deletion technique for a specific table in the context of a data migration or conversion process. This error typically arises when you attempt to change the deletion technique for a table that has already completed the deletion process.
Cause: Deletion Process Completed: The primary cause of this error is that the deletion process for the specified table has already been executed and completed. Once the deletion is finalized, the deletion technique cannot be altered.
Configuration Issues: There may be a misconfiguration in the data migration settings or parameters that led to an attempt to change the deletion technique after the process was finalized.
Solution: Review Deletion Status: Check the status of the deletion process for the table in question. If the deletion has indeed been completed, you will not be able to change the deletion technique. Revert Changes: If you need to
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