A few months back I had a look at Microsoft Operations Manager (MOM) 2005. Then, a couple of weeks back, I noticed that one of my servers had the Microsoft Operations Manager 2005 Agent installed, as well as the Active Directory management pack helper object. I uninstalled the Microsoft Operations Manager 2005 agent from the Add/Remove programs applet in Control Panel, but when I went to remove the helper object I was greeted with the following error (and the MSI Installer logged event ID 11920 in the application log):

Active Directory Management Pack Helper Object
Service ‘MOM’ (MOM) failed to start. Verify that you have sufficient privileges to start system services.

Retrying the operation produced the same error, so I was forced to cancel, then confirm the cancellation, before finally receiving another error message (and the MSI Installer logged event ID 11725 in the application log):

Add or Remove Programs
Fatal error during installation.

The answer was found on the microsoft.public.mom newsgroup – I needed to reinstall the MOM agent before the AD management pack helper object could be removed but there was a slight complication because I no longer have a MOM server (I deleted my virtual MOM server after finishing my testing). Manual agent installation is possible, but I needed to supply false details for the management group name and management server in order to let the installation take place with a warning that the agent would keep retrying to contact the server (all other settings were left at their defaults).

Once the agent installation was complete, it was a straightforward operation to remove the Active Directory management pack helper object, before uninstalling the MOM agent (successfully indicated by MSI Installer event ID 11724 in the application log).

It’s a simple enough workaround but represents lousy design on the part of the MOM agent/management pack installers – surely any child helper object installations should be identified before a parent agent will allow itself to be uninstalled?