Get-Mailbox cmdlet returns value of the legacy msExchHomeServerName attribute

Symptoms:

PowerShell cmdlets Get-Mailbox, Get-CASMailbox and Get-Recipient returns the ServerName icorrectly.

Example:

Get-Recipient jsmith | fl Name, ServerName, DataBase

Name       : Smith, John
ServerName : EX-LON1
Database   : LON-DB01

# find out on which server has the active copy of the database

Get-MailboxDatabase LON-DB01 | fl Name, Server

Name   : LON-DB01
Server : EX-LON02

Reason:

Get-Mailbox, Get-CASMailbox and Get-Recipient returns the value of the legacy msExchHomeServerName attribute which is updated when the mailbox is created but not updated later anymore due to a change in introduced in Exchange 2010

More Information:

Exchange 2010: HomeMTA and msExchHomeServerName are not updated on mailboxes.

homeMTA points to Active Directory object that have been deleted

Symptoms:

After uninstalling Exchange server and removing its Active Directory object  Event ID 2937 logged in Application log on an Exchange server and/or Warning “One or more Objects properties are pointing to Active Directory deleted objects” is recorded in SCOM.

Example event logged in Event log
Log Name:      Application
Source:        MSExchange ADAccess
Event ID:      2937
Task Category: Validation
Level:         Warning
Computer:      EX1-LON.adatum.com
Description:
Process powershell.exe (PID=12345). Object [CN=Doe\, John, OU=Users,OU=London, ,DC=Adatum,DC=com]. Property [HomeMTA] is set to value [adatum.com/Configuration/Deleted Objects/Microsoft MTA
DEL:aae571ff-19d3-bbcc-bf8a-eed91e496ea1], it is pointing to the Deleted Objects container in Active Directory. This property should be fixed as soon as possible.

SCOM warning:
Process mmc.exe (PID=67890). Object [CN=Doe\, John, OU=Users,OU=London, ,DC=Adatum,DC=com]. Property [HomeMTA] is set to value [adatum.com/Configuration/Deleted Objects/Microsoft MTA
DEL:aae571ff-19d3-bbcc-bf8a-eed91e496ea1], it is pointing to the Deleted Objects container in Active Directory. This property should be fixed as soon as possible.
EventSourceName: MSExchange ADAccess

Knowledge: http://go.microsoft.com/fwlink/?LinkID=67336&id=D00ED0ED-D9B5-48DF-9FF7-32F1A9CC592B

Computer: EX1-LON.adatum.com

Note: process name can be different depending on what process accessed the object

Resolution:
Generally  recommended solution in MS Article “One or more Objects properties are pointing to Active Directory deleted objects” solves the issue except if on the object in question has the msExchHomeServerName attribute point to an Exchange server which no longer exist.

In this case running Get-Mailbox <Alias> | Update-Recipient has no effect.
To resolve the issue when both homeMTA and msExchHomeServerName attribute have invalid values, run:
$MBX = Get-Mailbox -Identity ‘Doe, John’
Set-Mailbox $MBX -Database $MBX.Database -Confirm:$true -Force -Verbose

Source:
http://www.yusufozturk.info/windows-powershell/how-to-fix-incorrect-msexchhomeservername-attribute-after-removing-an-exchange-mailbox.html

Note: alert might not be cleared in SCOM up to 24 hours