I’m currently working on an Exchange 2007 to Office 365 staged migration for a client of ours. Some users are using Outlook 2013 and others are using older versions such as 2007. Outlook 2007 users havn’t been affected by this, however the Outlook 2013 users have.

After an Outlook account has been configured manually to point to Office 365 and after the user either logs off or the PC is restarted, Outlook reverts back to looking at the local Exchange server address. (Not good in this scenario, users will experience credential pop-up boxes etc). The way to get round this issue is to disable the Autodiscover feature in Outlook 2013 so it doesn’t automatically go to the nearest DC/Exchange server for the user details….

Outlook generically uses 5 different methods to connect to Exchange:

– SCP object lookup
– Root domain query based on your primary SMTP address
– Query for the AutoDiscover domain
– HTTP redirect
– SRV record query in DNS

To disable Autodiscover in OUtlook 2013, carry out the following:

Navigate to HKEY_CURRENT_USER\Software\Policies\Microsoft\Office\15.0\Outlook\AutoDiscover

Create the following Keys (depending on requirements, change to desired values):
“ExcludeScpLookup”=dword:00000001
“ExcludeHttpsRootDomain”=dword:00000000
“ExcludeHttpsAutoDiscoverDomain”=dword:00000000
“ExcludeHttpRedirect”=dword:00000000
“ExcludeSrvRecord”=dword:00000000