Message type: E = Error
Message class:  CNV20400 - Message class CNV20400 
Message number: 201
Message text: Start optimization of controlling area merge in test mode
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 CNV20400201 typically relates to issues encountered during the optimization process of a controlling area merge in a system that is using the SAP Conversion and Migration tools. This error can occur when you are trying to execute a merge of controlling areas in test mode, and it indicates that there is a problem with the configuration or data that needs to be addressed before proceeding.
Cause: Data Inconsistencies: There may be inconsistencies in the data related to the controlling areas that are being merged. This could include issues with master data, transaction data, or configuration settings.
Configuration Issues: The controlling areas may not be properly configured for merging, or there may be settings that are not compatible with the merge process. Authorization Issues: The user executing the merge may not have the necessary authorizations to perform the operation. Technical Errors: There could be underlying technical issues, such as database locks or
 Get instant SAP help. Sign up for our Free Essentials Plan.
Get instant SAP help. Sign up for our Free Essentials Plan. 
CNV20400200 Start optimization of controlling area merge
Self-Explanatory Message Since SAP believes that this specific error message is 'self-explanatory,' no more information has been given.The majority of...
CNV20400100 Error updating Fields Status with error &1
Self-Explanatory Message Since SAP believes that this specific error message is 'self-explanatory,' no more information has been given.The majority of...
CNV20400202 Optimization: Convert fields from split package also in merge package
 Optimization: Convert fields from split package also in merge package This optimization step checks if all table fields which are converted in the sp...
CNV20400203 Field &1-&2 was converted in split, but is not in CNVFIELDS for merge
Self-Explanatory Message Since SAP believes that this specific error message is 'self-explanatory,' no more information has been given.The majority of...
Click on this link to search all SAP messages.