Message type: E = Error
Message class:  CNV_MBT_46 - PCL message class 
Message number: 423
Message text: Select only one row
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 CNV_MBT_46423 typically occurs during data migration processes, particularly when using the SAP S/4HANA Migration Cockpit or similar tools. This error indicates that the system expects only one row to be selected from a dataset, but multiple rows are being returned or selected.
Cause: Multiple Rows Returned: The most common cause of this error is that the query or selection criteria used to fetch data is returning multiple rows instead of a single row. This can happen due to: Incorrect filtering conditions in the selection criteria. Data inconsistencies or duplicates in the source data. Misconfiguration in the migration settings. Data Model Issues: The underlying data model may not be designed to ensure uniqueness for the selected criteria, leading to multiple records being returned.
Solution: Review Selection Criteria: Check the selection criteria used in the migration process. Ensure that the criteria are specific enough to return only one row. You may need to refine the filters
 Get instant SAP help. Sign up for our Free Essentials Plan.
Get instant SAP help. Sign up for our Free Essentials Plan. 
CNV_MBT_46422 The source and target process type already exists
Self-Explanatory Message Since SAP believes that this specific error message is 'self-explanatory,' no more information has been given.The majority of...
CNV_MBT_46421 Target process type does not exist
Self-Explanatory Message Since SAP believes that this specific error message is 'self-explanatory,' no more information has been given.The majority of...
CNV_MBT_46424 Package &1 already exists; enter a non-existing (unique) pack id
Self-Explanatory Message Since SAP believes that this specific error message is 'self-explanatory,' no more information has been given.The majority of...
CNV_MBT_46425 Package &1 does not exist or not active
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.