When You install oem12c release 3 as upgrade on previous version and update all agents on remote hosts to actual version, there are one more step to end entire process – remove old binaries of previous agent. This will be done later, so don’t hurry with this operation. Be sure first that new one agent is working correctly.
001. Go to Setup -> Manage Cloud Control -> Upgrade Agents
Select second tab: Post Agent Upgrade Task and click on “Add” button.
002. Select agent from list (multi-selectable, hold Ctrl to select more than one row). They will be added to list.
Click Submit on next page.
003. After a while job will be completed.
004. You can check job details, but is everything works fine (success), this step is not needed.
When fail – come here and check what is a source of problem…
Overlook on logs…