Outlook 2016-2019 stuck on opening

Question

Hi guys,

We've 2 Exchange 2016 CU15 servers on premise.

Since 2 weeks, our users with Outlook 2016 or 2019 have random issues to open their Outlook clients : the app takes several minutes to open. Sometimes, no.

We've tried to disable all add-in, not better, try online mode / cache mode : not better.
Tried to debug connectivity with MRCA : nothing wrong.
With all Office 2019 (up to date or not) : same error.
With a Win10 up to date or not : same error.
Disable AV, not better.

With Outlook 2010 or 2013 : no problem.

So I thought we've an HTTP problem on our servers, as Outlook 2013 use RPC.

I don't know how to move forward on this problem.

Answer 1

Sorry for the response time.
Last week, we had a power cut at the office, so I’ve shutdown all our network equipments whose FW : since that, no more problem.

Answer 2

Hi @WebGTA ,

Users with Outlook 2016 or 2019 have random issues to open their Outlook clients : the app takes several minutes to open. Sometimes, no.

Does the issue occur to multiple users at the same time, or it randomly occur in different Outlook clients of different users?
Are these problematic users all connect from an external domain or all connected within the domain? it is suggested for you to try different network environments for these users and see if the issue has any difference.

As I know, Outlook client will go through multiple steps during the startup process, such as Processing or Loading Profile. So, which step did you get stuck for a long time?
As a usually workaround, it is suggested for you to exit your Outlook and re-start it in safe mode (Press Win + R, type “outlook /safe”, press Enter.), select the same profile and check if it could be opened normally. If everything could work fine in Outlook safe mode, then try re-start your Outlook normally and see if the stuck issue could be resolved.

By the way, you could also try the other workarounds in these articles and see if it works.
Outlook 2016/2019/365 Hangs At Processing, Starting Or Loading Profile Screen
(Please Note: Since the web site is not hosted by Microsoft, the link may change without notice. Microsoft does not guarantee the accuracy of this information.)

Any update, please feel free to post back.

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Answer 3

Additionally, take a look at the Exchange servers too.

• Do they have a high load when this occurs?
• Is there anything logged to the Event Viewer? Note that there are multiple logs for Exchange.

Also note that you are a couple of CUs behind for Exchange 2016. The most recent one is CU18. Apply the latest CU to make sure we are not troubleshooting an issue here that has already been solved. For instance; MSExchangeMapiMailboxAppPool causes prolonged 100% CPU in Exchange Server 2019 and 2016

If it is hanging during the AutoDiscover process, then you could consider disabling the AutoDiscover methods which are not configured for your environment.
See: Outlook 2016 implementation of Autodiscover

Answer 4

Thank's for reply.

When the problem occurs, everyone using Outlook 2019 is impacted during several minutes, then it works suddenly.
All computers are in a AD 2016 domain, we don't used OL Anywhere, only OWA for some external users (no problem with OWA).

On servers side, no cpu load, nothing in the EV.

I've tried to disable mapi (MapiHttpDisabled=1) on my computer, not better.
Disable autodiscover, same issue.