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.
Symptoms:
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.
Cause:
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.
Workaround:
After a migration batch completes, perform aniisreset 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.
Thanks,
Fable