Outlook 2016 autodiscover slow with hosted Exchange

We have a large amount of clients that use hosted Exchange for their email service.  As we started to roll out Office 2016 we noticed that it was taking an extremely long time for the autodiscover to detect the account settings.  In most cases it would be in excess of 10 minutes.  As Outlook 2016 no longer lets you manually setup Exchange accounts it was extremely frustrating. The problem s caused by a bug in Outlook 2016.  All hosted Exchange services use the HTTP redirection method for autodiscover to work correctly.  However Outlook 2016 will try the HTTPS root domain and HTTPS autodiscover domain first.  For some reason Outlook 2016 tries each of those methods 11 times at approximately 30 seconds each and this is what causes such a large delay.  The below registry settings will force Outlook to go directly to the HTTP redirection method and allow the account to be setup nearly instantly.

Windows Registry Editor Version 5.00

[HKEY_CURRENT_USER\SOFTWARE\Microsoft\Office\16.0\Outlook\AutoDiscover]
“ExcludeHttpsRootDomain”=dword:00000001
“ExcludeHttpsAutoDiscoverDomain”=dword:00000001

Hopefully Microsoft will provide an update to resolve this issue soon.


   2 Comments


  1. Lester Clayton
      11/24/2015

    Thank you so much for this – it worked perfectly here. This is definitely a change in the way Autodiscover works. What makes it more frustrating is that the Microsoft Connectivity Analyser will take 30 seconds to do all 4 Autodiscover tests – but their own product takes 11 times as long! 😉

  2. Atom B
      03/22/2016

    WOW! Worked for me like a charm. When your doing several of these or have to redo them or are trying to troubleshoot something and each time it takes 15-20mins it is so annoying. I closed Outlook, Added the two Registry Keys, Closed the Registry, Went to the Control Panel, Added the Exchange Email Account in under a min, then opened Outlook and it worked. THANK YOU!!

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