Today I went to multi-home a few agents to my SCOM 2012 network and was presented with the following error:
The Management Group Configuration could not be saved.
In my case, the issue was that SCOM had already entered the new SCOM Management Group details into the registry, so trying to add it again into the Operations Manager Agent Control Panel Applet caused the error. So fire up “Regedit” and navigate to HKLMSystemCurrentControlSetServicesHealthServiceParametersManagement Groups
Then find the appropriate management group and delete it from the registry and restart the healthservice!
Now try and add it back into the control panel applet again. If that doesn’t work, try uninstalling the agent and then reinstalling it. I’ve tried both options and both worked for me.