Start your web browser, go to https://vcenter server name or IP/mob
Select and copy the name of the plug-in you want to remove from the list of values under Properties. For a list of default plug-ins, see the Additional Information section of this article.
Click UnregisterExtension. A new window appears.
Paste the name of the plug-in and click Invoke Method. This removes the plug-in.
Close the window.
Refresh the Managed Object Type:ManagedObjectReference:ExtensionManager window to verify that the plug-in is removed successfully.
Source: VMware KB 1025360 – Removing unwanted plug-ins from vCenter Server