Message type: E = Error
Message class:  CNV - Conversion: Messages for Conversion Services (CNCC) 
Message number: 857
Message text: Reloading is not possible for table &; WHERE clauses are used
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.
To make things easier, more detailed information is frequently added to describe the issue, how to fix it, and the necessary steps or configuration modifications.
Unfortunately, there isn't any extra information in this error notice.
First, use our AnswerBot below to get a possible cause and solution (requires a premium subscription).
Also, review the in-depth Common Questions & Answers listed below; you could discover a solution there or be able to connect with others who have faced similar challenges.
You can also try searching the SAP support portal (support.sap.com) but you need a special user ID to access it. It is possible that an SAP support note exists that provides additional details about the mistake or even steps for fixing it.
The SAP error message CNV857 indicates that reloading data into a specific table is not possible because WHERE clauses are being used. This typically occurs in the context of data migration or data transfer processes, particularly when using SAP's data migration tools or during system conversions.
Cause: The error arises when the system detects that the data reload operation cannot be performed due to the presence of WHERE clauses in the data transfer or migration process. WHERE clauses are used to filter data, and in certain scenarios, they can prevent the system from executing a complete reload of the data into the specified table.
Solution: To resolve this error, you can consider the following steps: Review the Data Transfer Process: Check the configuration of the data transfer or migration process. Ensure that the WHERE clauses are necessary and correctly defined. If they are not needed, consider removing them. Adjust the Data Load Method: If the WHERE
 Get instant SAP help. Sign up for our Free Essentials Plan.
Get instant SAP help. Sign up for our Free Essentials Plan. 
CNV856 Reloading is not possible for table &. Scen. &, and table is not empty.
Self-Explanatory Message Since SAP believes that this specific error message is 'self-explanatory,' no more information has been given.The majority of...
CNV855 Reloading is not possible for table &. Not all entries are in the cluster
Self-Explanatory Message Since SAP believes that this specific error message is 'self-explanatory,' no more information has been given.The majority of...
CNV858 No records were selected for table &; reload is not necessary
Self-Explanatory Message Since SAP believes that this specific error message is 'self-explanatory,' no more information has been given.The majority of...
CNV859 Note that already generated programs are not deleted
What causes this issue?  You decided to undo the selection of some tables for backup. These tables have been deselected. However the existing generate...
Click on this link to search all SAP messages.