Exchange slowness - Exch 2013 on prem to outlook 2016.

[_techie_]

Exchange 2013 CU 23 on-prem slowness with outlook 2016 on Windows 10 LTSC 2019.

 

I'm struggling a bit at the moment with slowness of Outlook 2016 on on-prem domain joined machines. Slowness occurs during outlook loading and when navigating the application. Takes around 45-60 secs to load the application.

 

Occurs with most staff using mandatory profiles using outlook in non-cached mode (online with exchange).

 

If I enable cached mode to test, loading times improve to around 10-20 secs and using navigation (now usable).

 

If I stick with non-cached mode, using outlook in safe mode, the app loads in around 6 seconds. But navigating around is still troublesome with frequent hangs of the application.

 

Only changes of late are to:

1) Enable MAPI over HTTP on the exchange server (to remove a prompt for password that was occuring when loading outlook).

2) install .net 4.8 on clients and on exchange box.

3) update ESET security product on clients and exchange box.

 

Any ideas as to what's happening/causing slowness?

 

Cheers

[chaplic]

Autodiscover.

 

Outlook tries a number of ways to find your mailbox.

 

If you've not got any O365 email, you can definetly disable the autodiscovers that attempt to connect to O365

 

You're probably using SCP to find your mailbox, so disable all but that and see what happens

 

 

 

Unexpected Autodiscover behavior if settings under the \Autodiscover key - Outlook | Microsoft Docs

 

The link above talks about the problems that can be caused when settings are on (so the opposite of your issue) but does give the keys

 

 

I would set the following to one and see what happens. If it looks good, also test free/busy lookup and setting an out of office

• ExcludeHttpRedirect
  
• ExcludeHttpsAutoDiscoverDomain
  
• ExcludeHttpsRootDomain
  
• ExcludeSrvRecord
  
• ExcludeExplicitO365Endpoint
  

[_techie_]

Turned out to be an issue with the vNic dropping random pings. Managed to get a new vNic added and back up and running within the hour. Thanks for your help though, learnt a lot in the last few days.