Exchange 2013 Mailboxes – MailboxGuid @ SMTP Domain Is The New Endpoint In Outlook

MS Exchange

All Exchange admins are so used to seeing the name of the server / fqdn of the VIP in the server entry of the outlook profile. That is a thing of the past in Exchange 2013!

The server entry or the connection endpoint for Outlook 2007+ clients which connects to an Exchange 2013 mailbox is the “mailbox guid @ the primary smtp address of the user”. Let me explain the new concept with an example. My mailbox has a primary smtp address of and the server entry in my outlook profile is as shown below.

Users connect to their mailbox guid@smtp domain

This is expected behaviour in 2013 and the server entry will tie in nicely with my mailbox guid.

Mailbxo Guid

This change has helped to get rid of the message “Your administrator has made a change to your mailbox. Please restart” in the 2013 world. Next time you play with the outlook profile of a 2013 user, don’t panic ;)

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  1. HI Rajith-
    thanks for the wonderful articular, is there a way to rename the GUID for all users to single address,i.e having an internal exchange server name so when we need to configure any user mailbox manually then the support team knows what’s the server address “similar to exchange 2010”.


  2. Thanks for the article. I have one question. I want to know whch exchange server guid is this in case I have more than two CAS servers. Thanks

  3. Hi ,
    I have recently installed the exchange 2013 as follow
    one CAS and Two mail box DAG
    so I was facing similar issue outlook clients were not able not see the CAS
    so here are the magic solution :
    1-created SRV record for auto discover
    right click the FLZ, click Other New Records. Select Service Location (SRV). Enter _autodiscover as the Service, _tcp as the Protocal, 443 for the Port, and as the Host offering this service. Hit OK.
    2-created A record for auto discover and the IP same as CAS IP
    3-created an internal Certificate in CAS server “create a new certificate request ” and include all names such CAS , MB’s , Auto discover this step to avoid the warning message during outlook setup because self-sign certificates in ex2013 not helping
    after that I have tested the outlook and was working fine NO GUID and NO certificates warning

  4. Hi Rajith, thanks a ton for the blog post.

    I have a question for you. We have a script that mounts PRF files and modifies them with new user info so that we can basically automate the importing of Outlook settings to our remote users who aren’t part of the domain where our Exchange server operates.

    This new GUID requirement forces us to hard code a custom Mail address for each user now in the PRF. Meaning, before we could use and now we have to use

    Do you know how I could go about querying the Exchange GUID for all our users in our Active Directory?


  5. HI Rajith,

    After get the Guid of Exchange 2013 user, create Outlook 2010 profile for it like as your instruction but cant do that, the warning is
    “…..cannot resolved”
    BTW: my exchange 2013 roles as CAS and mailbox database ; Firewall is turned off


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