Unique Constraint Error on PS_MESSAGE_LOG

If you are getting a unique constraint error on PS_MESSAGE_LOG in the process monitor like this:

ORA-00001: unique constraint (SYSADM.PS_MESSAGE_LOG) violated

The cause is generally a locked user account that has a scheduled job. Clear all their errors and recurrences or unlock the account. You will see this error on un-related jobs for other users and not the locked user so it is confusing.

For additional information see the Oracle Support article 640200.1