I ran into this message when attempting to delete a SQL Job. Somehow a subplan was orphaned and not allowing me to delete the job.
First I got the Job_id by right clicking on the job and scripting the drop.
The script will contain the job_id
Now I searched for the Job_id in the System Maintenance sub plans.
I then used the delete statement above to remove the sub plan. Then I was able to go back to the jobs and delete the job.
Thanks to Moshin’s DBA Blog for help on this. Moshin’s DBA BLog