In order to remove a disconnected Altaro VM Backup installation from CMC, you can follow the steps below:

1. Once you're logged in to CMC, navigate to [Setup] > [Customer Infrastructure] > [Altaro Installations]. Locate the disconnected installation and click [Manage]
   
   
   
   
2. This will take you to the management screen of that particular Altaro VM Backup installation. From here locate the 'Bin' icon and click on it:
   
   
   
   
3. You will then be prompted by a message notifying you that this installation will be completely removed from CMC and you won't be able to manage/monitor it any longer.
   
   Only do this if your installation is removed and no longer require it to be added to CMC. Click [Yes] to proceed.
   
   
   
   
4. Your Altaro VM backup installation will now successfully be removed from CMC