Message type: E = Error
Message class:  CNV_10996 - Messages for archive conversion 
Message number: 012
Message text: Job &1 is already scheduled or has run successfully.
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_10996012 indicates that a job with the specified name (&1) is either already scheduled or has been executed successfully. This error typically arises in the context of data migration or conversion processes, particularly when using SAP's Conversion Tools or during system migrations.
Cause: Job Already Scheduled: The job you are trying to schedule is already in the job queue. This can happen if the job was previously scheduled and not yet completed. Job Already Executed: The job has already run successfully, and the system does not allow it to be executed again without a specific reason (e.g., re-running a migration job). Duplicate Job Submission: There may be an attempt to submit the same job multiple times, leading to this conflict.
Solution: Check Job Status: Go to transaction code SM37 (Job Monitoring) in SAP. Enter the job name and check its status. If it is running, you may need to wait for it to complete.
 Get instant SAP help. Sign up for our Free Essentials Plan.
Get instant SAP help. Sign up for our Free Essentials Plan. 
CNV_10996011 Package is not org-dependent.
Self-Explanatory Message Since SAP believes that this specific error message is 'self-explanatory,' no more information has been given.The majority of...
CNV_10996010 &1 of &2 objects processed, &3 changed.
Self-Explanatory Message Since SAP believes that this specific error message is 'self-explanatory,' no more information has been given.The majority of...
CNV_10996013 Archive run &1 &2 selected for conversion.
Self-Explanatory Message Since SAP believes that this specific error message is 'self-explanatory,' no more information has been given.The majority of...
CNV_10996014 In &1 objects, &2 lines were read and &3 lines were changed.
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.