Our users complain about being prompted by outlook to enter their credentials when we are switching nodes in the CCR cluster - this is when the admin uses Move-ClusteredMailboxServer command primarily when patching etc. We've never paid attention to prompts mainly assuming not an issue, but I thought I'd check with the experts - are those prompts normal or is there something that can be fixed here? Thank you in advance

Much of this can be mitigated by ensuring Outlook mapi clients are in cache mode and have the latest service packs and rollups applied for both Exchange and Office/Outlook. I saw this in mainly early on with 2007 RTM and Office 2007 RTM. Failover user experience especially improved with SP2 of Office 2007.

It’s all about outlook’s connection logic that tries to reconnect to Exchange after disconnect. Outlook will pass a complicated sequence of checks in order to verify if some connections don’t succeed and prompt window needs to be appeared The biggest influence on outlook giving popups is the network, and the response from exchange server after the failover. The responses and the connection logic change depending on the time cost to failover, server conditions, network conditions, and client conditions. The connection logic is also affected by the different combination between windows client versions and outlook client versions However, the best and recommended solution is to install outlook 2007 SP2 as Andy said. It is in this version that many changes and optimizations have been made to the connection logic KB 956531 also covered such improvement under certain network. In most scenarios, you don’t need to use the KB to change the behavior of the connection logic. Outlook 2007 SP2 would be enough James Luo TechNet Subscriber Support in forum If you have any feedback on our support, please contact tngfb@microsoft.com Please remember to click Mark as Answer on the post that helps you, and to click Unmark as Answer if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread.

we use both 2007 and 2010 outlook versions, both being fully patched and this behaviour is being experienced by all users with no exceptions, BUT only when we are switching from one CCR node to another. the KB article had no effect, but exchange itself is still on SP1 UR10 due to an Autonomy product being installed on CAS, which is what I'll try to upgrade

Note also that if you have any Outlook Add-ins or anything else outside of Outlook that hooks into it, you may see these issues as well.