Message type: E = Error
Message class:  CMM_MEV_GEN_BO - Messages for Accrual Document BO for PEV 
Message number: 013
Message text: Accrual document &1 &2 is locked by user &3
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 CMM_MEV_GEN_BO013 indicates that an accrual document is locked by a specific user. This typically occurs when a user is currently editing or processing the document, preventing other users from making changes or accessing it until the lock is released.
Cause: User Lock: The document is being edited by another user, which causes a lock on the document. Session Timeout: Sometimes, if a user has an open session that times out, the lock may not be released properly. System Error: Occasionally, system errors or crashes can lead to locks not being released as expected.
Solution: Wait and Retry: If the document is locked by another user, the simplest solution is to wait until that user has finished their work and the lock is released. Identify the User: Check who is currently locking the document (as indicated by the error message) and communicate with that user to see if they can release the lock. Transaction SM12:
 Get instant SAP help. Sign up for our Free Essentials Plan.
Get instant SAP help. Sign up for our Free Essentials Plan. 
CMM_MEV_GEN_BO012 Error while reading accrual document &1 &2
Self-Explanatory Message Since SAP believes that this specific error message is 'self-explanatory,' no more information has been given.The majority of...
CMM_MEV_GEN_BO011 Accrual document 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...
CMM_MEV_GEN_BO014 Specify key for accrual document
Self-Explanatory Message Since SAP believes that this specific error message is 'self-explanatory,' no more information has been given.The majority of...
CMM_MEV_GEN_BO015 Action not allowed
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.