As part of OpsMgr 2012 Upgrade, you will need to move all Agents reporting to the RMS as the Primary Management Server. If you have an OpsMgr 2007 R2 Server Core Agent reporting to an RMS I have outlined the steps I used to move the Agent from the RMS to a non-RMS (MS).

1.            Logon to the Server Core Server via RDP
2.            Open Task Manager
3.            You will need to hit Ctrl+Alt+End to access the GUI to ‘Start Task Manager’
4.            Click ‘Start task manager’
5.            Go to file, run, cmd.exe to open command prompt
6.            Open REGEDIT from command prompt
7.            Navigate to HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall
8.            Expand Uninstall and look for the key that matches the installation of the SCOM Agent
9.            Double click the Uninstall string with the GUID and copy the Value Data
10.         Paste the uninstall string into the command prompt and press enter

11.         You will see the following window

12.         Click Next, then click Modify

13.         Click Modify Management Group

14.         Ensure Specify Management Group information is checked

15.         Change the Management Server to point to the correct MS (non RMS) to prep for upgrade


16.         Click Next, then click Install


17.         Click Finish


18.         Open the command prompt you used in the steps above

19.         Stop the healthservice within server core by using the command below:
             net stop healthservice
20.         Go to the Operations Console, Administration, Agent Managed, delete the Agent
21.         Start the healthservice on server core by using the command below:
             net start healthservice


22.         Go back to the Operations Console/Administration, ensure that the Agent is displayed in Agent Managed and is healthy.  It may take a few minutes to see the server core agent show in the console and in a healthy state