I've been getting asked this question a lot lately, and so I thought I would consolidate the conditions that I have been able to identify that will cause the unwelcomed prompt in Outlook:
I'd imagine that some of the readers that arrive at this post are here as a result of having Outlook issues. As a gratuitous plug, in case you haven't tried it or are not aware of it, please take a look at the OFFCAT- the Office Configuration and Analysis Tool (available HERE ) that allows you to scan an Office/Outlook installation and review known and potential issues.
You can expect to see the prompt under the following conditions:
If the RPCClientAccessServer property changes.
-Cross AD site mailbox moves may trigger this, as each AD site may have a different RPC Client Access Array.
-If you are not using a CAS Array, if the RPC endpoint changes after a mailbox move. An example of this is when a user on the source database has a specific CAS as its RPC endpoint, and the destination of the mailbox move has a different CAS specified as its RPC endpoint.
If the Public Folder hierarchy server changes after a mailbox move. (if get-mailboxdatabase|fl identity, publicfolderdatabase are different between source and target databases )
If The user does has additional mailboxes open in Outlook where the additional mailboxes do not meet the above conditions when being moved. So, if you have Joe User's mailbox open in Outlook, and they are moved from Server A/DB A, which has an RPC endpoint of CASARRAYA, and they are moved to Server B/DB B, with an RPC endpoint of CASARRAYB, then you will receive the prompt after Joe User's mailbox is moved. There are additional considerations in this scenario, regarding ALLOWCROSSSITERPCACCESS, which are detailed in the EHLO blog post "RPC Client Access Cross-Site Connectivity Changes"
If you are on Outlook 2013, and your mailbox is moved from Exchange 2010 to Exchange 2013, and you do not have http://support.microsoft.com/kb/2934750 installed. Key takeaway: keep Outlook up to date, as there are other, earlier hotfixes that also addressed the prompt issue.
Certain conditions when you have a CAS/Mailbox server that is also hosting your public folder database:
You can expect to see these prompts when a public folder exists on a multirole server that is part of the Exchange Server 2010 CAS array. This issue occurs because the VIP of the CAS array is being returned to the client instead of the hosting server.
The problem arises when an Outlook client connects to the CAS array and initially, if outlook connects to the CAS array member that contains the PF role, then Outlook converges all connections and displays both the Public and Private logons as one single connection (the CAS array name). When the Clients IP address changes, and it Re-connects, if it gets connected to a CAS array member that does not have the PF server, then we get an ECwrong server Response from Exchange, Outlook in its reconnect logic Cannot follow the Redirection Result that contains the correct PF server name, and displays the Error "The Administrator has made a change that requires you restart Outlook"
If you use the -DoNotPreserveMailboxSignature parameter with the New-MoveRequest cmdlet
You have the option to completely suppress the dialog:
How to suppress the pop-up "The Microsoft Exchange administrator has made a change that requires you quit and restart Outlook" in Outlook 2010
• Uncheck the option “Show Microsoft Exchange Messages” from the Outlook icon on taskbar, and test the behavior.
This setting is controlled by the registry value..
Value: 1 (on) / 0 (off)
RPC Client Access Cross-Site Connectivity Changes
Restart Outlook prompt post Exchange 2010 SP2 rollup 3+
Obviating Outlook Client Restarts after Mailbox Moves
(Updated to fix link to Offcat)