Autodiscover causes Outlook to hang on start for at least 30sec

The loading of profiles in Outlook 2016 can use up to 5 minutes

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try this reg key (this is valid for office365, office 2016 click-to-run and office 2019)

[HKEY_CURRENT_USER\Software\Microsoft\office\16.0\outlook\autodiscover]
 "DisableAutodiscoverV2Service"=dword:00000001

or

[HKEY_CURRENT_USER\Software\Policies\Microsoft\office\16.0\outlook\autodiscover]
 "DisableAutodiscoverV2Service"=dword:00000001

 

starting with version 1710 Build 16.0.8625.2121 Microsoft introduced a new autodiscover feature which always asks https://outlook.office365.com for the exchange server information.
the response is a http 302 redirect to https://autodiscover.yourdomain/autodiscover/autodiscover.json?...."

if there is a dns entry autodiscover.yourdomain, outlook tries to connect on port 443. But if nothing is listening on this port outlook waits for a timeout which is 20sek after that timeout the normal autodiscovery kicks in 

if you only use the http redirect autodiscover feature this is a problem because nothing should listen on autodiscover.youdomain port 443 because if the ssl cert doesn't match you get a certifacte warning

starting with version 1810 Build 16.0.11001.20074 Microsoft introduced a new registry key to disable this new autodiscover behavior:

DisableAutodiscoverV2Service"=dword:00000001

I use the following reg keys because i only need active directory and http redirect for autodiscover:

[HKEY_CURRENT_USER\Software\Policies\Microsoft\office\16.0\outlook\autodiscover]
 "excludelastknowngoodurl"=dword:00000000
 "excludescplookup"=dword:00000000
 "excludehttpsrootdomain"=dword:00000001
 "excludehttpsautodiscoverdomain"=dword:00000001
 "excludehttpredirect"=dword:00000000
 "excludesrvrecord"=dword:00000001
 "excludeexplicito365endpoint"=dword:00000001
 "DisableAutodiscoverV2Service"=dword:00000001

 

here is a good kb entry for autodiscover but it does not mention the disableautodiscoverv2service reg key
https://support.microsoft.com/en-us/help/3211279/outlook-2016-implementation-of-autodiscover

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