Known issue - Outlook stays disconnected after migrating mailbox from Exchange 2010 to Exchange 2013 SP1 RRS feed

  • General discussion

  • Hey All,

    I wanted to start this thread because for the first time since working on this, I have official confirmation from Microsoft that this is a known issue.

    This has been discussed in various posts such as here and here, This post is actually a semi cross-post of another post of mine in this thread. This same behavior has been linked to this KB. Although the same behavior is observed, I am able to confirm that the two issues are unrelated. I was able to observe this problem with a newer version of Outlook 2013 than mentioned in the KB as well as in Outlook 2010.


    Consider this scenario:

    - Existing Exchange 2010 environment with new Exchange 2013 Mailbox and CAS servers introduced. All Exchange 2010 servers on SP3 CU 5. Exchange 2013 Servers on SP1 CU 5

    - Clients include Outlook 2010 SP1 and Outlook 2013 SP1

    This procedure is followed to replicate the issue:

    - Create new mailbox using Exchange 2010 console and add it in an Exchange 2010 Mailbox Database

    - Create Outlook profiles in both Outlook 2010 and Outlook 2013. Outlook should work as expected at this point.

    - From Exchange 2013, initiate a new migration for the mailbox in question. 

    - When the migration finishes Outlook displays a pop-up and asks to be restarted

    - After restart, Outlook stays disconnected. Looking at the Outlook "Connection Status" screen the client tries to connect to the Exchange 2013 server but the connection is redirected back to the 2010 server.


    According to Microsoft this is a known issue. It occurs because when a mailbox is moved to Exchange 2013 from Exchange 2010, the mailbox itself still has a cache entry that points the client back to the 2010 server. According to Microsoft, this cache expires after an "undetermined" time interval for Exchange 2013 SP1 up to CU4 and every "2 to 2.5 hours" in Exchange 2013 CU5. They could not reference a KB article with this info.


    After a migration batch completes, perform an iisreset on the Exchange 2013 CAS server. The following strategy can be followed to streamline the process of migrating multiple mailboxes:

    • Create a migration batch for a number of mailboxes. 
    • Select to "Manually Complete the batch" in the "New Local Mailbox Move" window. This process will migrate 95% of the mailbox and then stop. 
    • After 95% of the contents of each mailbox have been moved, the batch will stop syncing and show as "synced" on the migration window. Up to this point in the process users are able to use Outlook without any interruption and the move is invisible to them.
    • When you are ready to finish the migration, select to "Complete This Migration Batch" on the ECP Migration screen. At this time, users that have Outlook open will receive a prompt to restart it. When Outlook re-opens, it will show as "Disconnected" until the next step is performed.
    • Once the batch shows as "completed", perform an iisreset on the 2013 CAS server. At this time, Outlook will show as "Connected to Microsoft Exchange" and users will receive a second prompt to restart Outlook. After the second restart Outlook will be permanently connected to Exchange 2013.

    If you do not wish to perform an iisreset, there is an alternative way of forcing Outlook to reconnect:

    Microsoft has confirmed that recycling the following Application Pools forces Outlook to connect to Exchange 2013:

    Exchange 2013 CAS Server

    • MSExchangeAutodiscoverAppPool
    • MSExchangeRpcProxyFrontEndAppPool

    Exchange 2013 Mailbox Server:

    • MSExchangeAutodiscoverAppPool
    • MSExchangeRpcProxyAppPool

    If you decide to not perform an iisreset and opt for recycling the App Pools instead, be advised that after the AppPools are recycled, Outlook connects to Exchange and asks to be restarted. If you close Outlook and immediately open it again, you will be prompted with a username and password pop-up (At least I was in all my tests of this method.) This issue is resolved if, after you close Outlook, wait 5 to 10 minutes before re-opening it. You will not be prompted for a user/pass at this point.

    For those who choose to have the migration complete automatically: The cache entry that causes all this issue is cleared after about 2 to 2.5 hours if you are on Exchange 2013 CU5. In any case, it may be better if you have control over when the migration finishes by opting to complete it manually.

    There is currently no KB article referencing this issue and Microsoft cannot provide a time when a patch fixing this will be released.


    • Edited by tFable Thursday, August 21, 2014 1:49 AM
    Thursday, August 21, 2014 12:56 AM

All replies

  • Hi, I have seen this exact issue in different Customer environments - has 2013 CU6 made any difference? Cheers, Simon
    Friday, November 7, 2014 9:37 AM
  • Hi, I have seen this exact issue in different Customer environments - has 2013 CU6 made any difference? Cheers, Simon
    I haven't installed CU6 in my environment yet so I wouldn't know.  If you do, I would appreciate it if you let us know whether the behavior changed.
    Friday, November 7, 2014 3:52 PM
  • Happy to confirm that since applying CU6, the migrations are now running seamlessly :)
    Thursday, November 27, 2014 3:06 PM
  • We have the same problem. Exchange 2013 CU7 Exchange 2013 CU8.
    • Edited by AlexMurr Friday, March 27, 2015 12:27 PM
    Friday, March 27, 2015 12:26 PM
  • Hello Fable and thank you for that. I've been moving mailboxes around for now three hours between 2010 and 2013 until I've found your solution. Yes I can confirm that when I reboot the 2013 CAS server after mailbox move it works. Just installed Exchange 2013 CU8 to our Network production here. I was already scared that I haven't learned anyting about Exchange.



    • Edited by Robinion Thursday, April 23, 2015 5:11 PM
    Thursday, April 23, 2015 5:08 PM
  • I'm on Exchange CU9 with the same issues like on CU7 and CU8... 
    Tuesday, July 28, 2015 11:16 AM
  • Hi,

    not so nice to read this. The reboot of the CAS is not necessary. The cache refreshes after about 120 minutes and then user can connect. Just migrate them during the night and the next morning they should be fine. I've done it like that.



    Tuesday, July 28, 2015 12:04 PM
  • Issue still occurs with CU10 also.
    Friday, November 13, 2015 8:57 PM
  • In our environment where we are migrating mailboxes from Exchange 2010 to 2013 cu9..Outlook 2010/2013 will be in disconnected state which Is working fine once we repair the profile
    Saturday, November 14, 2015 8:40 AM
  • Hi,

    We get the same problem with Exchange 2016.

    You can also edit the Recycling Settings in IIS on the Exchange 2013/16 server for the 4 App bellow and set the fixed Intervals for refresh all 2 minutes during the migration time. :

    Exchange 2013/2016 CAS Server

    Exchange 2013/2016 Mailbox Server:

    When the migration finishes Outlook displays a pop-up and asks to be restarted. After restart, Outlook connect to the server automaticly after 1-2  mins max.



    Friday, December 11, 2015 9:48 AM
  • Hi All , 

    I'm in the process of migrating a medium size EX 2010 org to 2016 , I currently running into this problem . I was wondering if I could get two question answers .

    1. What are some of the side effects with restarting the APP pool on my Ex 2016 box   (Restart-WebAppPool MSExchangeAutodiscoverAppPool) for my end users. Most of my migrations will happen within business hours and I want to know if there are any side effects to do this action ? 

    2. Recycling Settings in IIS : MSExchangeAutodiscoverAppPool , MSExchangeRpcProxyAppPool.  Is this the  setting you modify ? 

    If So can any one comment on side effects of doing this with a production environment?  

    Oh, Third question ,  Is there a Ms Fix as the one posted is a work around when your doing medium / large org 

    Friday, June 23, 2017 2:03 PM
  • Thanks tFable for detailed description.

    Doing migration from ex2010 to ex2016 with latest CU. 

    Problem is that right after migration batch is created, users get popup to restart their outlook. Doing so keeps outlook in disconnected status.

    Recycling both app pools and do another send/receive in outlook will help (yes send and receive have to be done, or restart outlook).

    This is bad....

    Please mark as helpful if you find my contribution useful or as an answer if it does answer your question. That will encourage me - and others - to take time out to help you. Thank you! Off2work

    Tuesday, July 25, 2017 6:10 PM
  • No, Not any difference with CU6 either. Same ISsue

    Thanks and Regards, Mohammad Ahmad Siddiqui

    Saturday, October 28, 2017 1:18 PM