Kategorie: Windows, Exchange

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

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

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





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:


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



here is a good kb entry for autodiscover but it does not mention the disableautodiscoverv2service reg key


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