After you have installed Service Pack 1 for Exchange 2010 you find multiple event id 2937, source MSExchange ADAccess warnings.
“Process Microsoft.Exchange.AddressBook.Service.exe (PID=960). Object [CN=Username,OU=OU name,DC=domain,DC=local]. Property [HomeMTA] is set to value [domain.local/Configuration/Deleted Objects/Microsoft MTA
DEL:5e53dca2-cd75-4b28-a0cc-7f87392e1869], it is pointing to the Deleted Objects container in Active Directory. This property should be fixed as soon as possible.”
The process and username may vary.
Solution: When you run the “update-recipient recipientname” command from exchange management shell it will update the HomeMTA value to a good value. If you would like to run the setting for all your user account in one mailbox database use the following command: “get-mailbox -database “Mailbox Database” | update-recipient”
Source: Microsoft technet forum