When you delete Exchange Connector management pack without prior deleting the connector’s instances, you get the orphaned connectors in the SCSM console that you cannot delete. Even after you import the Exchange Connector management pack back, the situation stays as bad as before.
As many of you know, in Service Manager 2012 it is not easy to find out who exactly marked a Manual Activity as Completed. This information can be found in the history of the Manual Activity where the user is mentioned in the form of so-called 'Down-Level Logon Name' or DOMAIN\UserName. Needless to say that sometimes it is hard to realize that Contoso\josmi is actually John Smith.