Message type: E = Error
Message class:  CNV_MBT_DEX - DMIS Data Extract related messages 
Message number: 112
Message text: Data Selection has not yet been started
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_DEX112: Data Selection has not yet been started typically occurs in the context of data migration or data transfer processes, particularly when using the SAP S/4HANA Migration Cockpit or similar tools. This error indicates that the data selection process has not been initiated, which is a prerequisite for further actions in the migration process.
Cause: Data Selection Not Executed: The most common cause of this error is that the data selection step has not been executed. This step is crucial as it prepares the data for migration. Process Interruption: If the data selection process was interrupted or failed to complete, subsequent steps may not be able to proceed.
Configuration Issues: There may be configuration issues in the migration cockpit or the specific migration project that prevent the data selection from being initiated. User Permissions: The user may not have the necessary permissions to execute the data selection process.
Solution: Execute Data Selection: Ensure
 Get instant SAP help. Sign up for our Free Essentials Plan.
Get instant SAP help. Sign up for our Free Essentials Plan. 
CNV_MBT_DEX111 Export has been stopped
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_DEX110 Export of file & failed
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_DEX113 Preparation activity has not yet been executed
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_DEX114 & rows read from DMC_INDXCL
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.