Message type: E = Error
Message class:  CNV_MBT_KP - Knowledge pool 
Message number: 004
Message text: Select at least one line
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The SAP error message CNV_MBT_KP004: Select at least one line typically occurs in the context of data migration or conversion processes, particularly when using the SAP S/4HANA Migration Cockpit or similar tools. This error indicates that the user has not selected any entries or lines in a list where at least one selection is required to proceed with the operation.
Cause: No Selection Made: The most straightforward cause is that the user has not selected any rows or entries in the relevant table or list. Filter Settings: Sometimes, the filter settings may inadvertently hide all entries, leading to no visible selections. User Interface Issue: There may be a temporary glitch in the user interface that prevents selections from being registered.
Solution: Select an Entry: Ensure that you select at least one line or entry in the list before attempting to proceed with the operation. Check Filters: Review any active filters to ensure that they are not excluding
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