Message type: E = Error
Message class:  CNV_CMIS_A_20 - Message class for Cross-Client Customizing Comparison (SLO) 
Message number: 261
Message text: Processor assigned to selected entries
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_CMIS_A_20261 typically occurs in the context of data migration or conversion processes, particularly when using the SAP S/4HANA Migration Cockpit or similar tools. This error indicates that a processor has already been assigned to the selected entries, which can lead to conflicts or issues in processing.
Cause: Processor Assignment Conflict: The error arises when multiple entries are trying to be processed by the same processor simultaneously, or when an entry is already assigned to a processor that is currently busy or locked. Concurrency Issues: If multiple users or processes are trying to access or modify the same data entries at the same time, it can lead to this error. Incomplete Previous Processing: If a previous migration or processing step was not completed successfully, it might leave entries in a state that prevents new assignments.
Solution: Check Processor Status: Verify the status of the processor assigned to the entries. Ensure that it is
 Get instant SAP help. Sign up for our Free Essentials Plan.
Get instant SAP help. Sign up for our Free Essentials Plan. 
CNV_CMIS_A_20260 Enter Comment.
Self-Explanatory Message Since SAP believes that this specific error message is 'self-explanatory,' no more information has been given.The majority of...
CNV_CMIS_A_20259 Table with content could not be read
Self-Explanatory Message Since SAP believes that this specific error message is 'self-explanatory,' no more information has been given.The majority of...
CNV_CMIS_A_20262 Processor name left blank
Self-Explanatory Message Since SAP believes that this specific error message is 'self-explanatory,' no more information has been given.The majority of...
CNV_CMIS_A_20263 Mark rows in order to assign processor
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.