Message type: E = Error
Message class:  CNV_20100 - Messageclass for chart of account conversion 
Message number: 400
Message text: Unsaved data will be lost. Do you want to save?
Since SAP believes that this specific error message is 'self-explanatory,' no more information has been given.The majority of messages in the SAP system have a message text, however this is frequently insufficient to comprehend or resolve the problem.
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The SAP error message CNV_20100400 typically occurs during data migration or conversion processes, particularly when using the SAP S/4HANA Migration Cockpit or similar tools. This message indicates that there are unsaved changes in the current session, and the system is prompting the user to decide whether to save those changes or discard them.
Cause: Unsaved Changes: The primary cause of this error is that there are changes made in the data entry fields that have not been saved. This can happen if the user navigates away from the screen or tries to execute a function without saving the current data. Session Timeout: If the session has been idle for a while, it may prompt this message when the user tries to perform an action. Data Migration Process: During data migration, if the user is in the middle of entering or modifying data, the system will alert them to save their work to prevent data
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