Message type: E = Error
Message class:  CNV - Conversion: Messages for Conversion Services (CNCC) 
Message number: 851
Message text: Reloading is not possible for table &. Optimized cluster method is used.
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The SAP error message "CNV851 Reloading is not possible for table &. Optimized cluster method is used." typically occurs during data migration or data transfer processes, particularly when using the SAP Landscape Transformation (SLT) or SAP Data Services tools. This error indicates that the system is unable to reload data into a specific table because the optimized cluster method is being used for that table.
Cause: Optimized Cluster Tables: The error arises because the table in question is an optimized cluster table (e.g., table types like ACDOCA, which is used in S/4HANA). These tables have specific data storage and access methods that do not support certain operations, such as reloading data in the same way as standard tables. Data Migration Process: During data migration, if the process attempts to reload data into a table that is not designed to handle such operations, this error can occur.
Configuration Issues: There may be configuration settings in
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