Hello Franky,
As regards to your concern about the Nov security update for Exchange 2019 CU13, I checked the official blog about this update, but so far haven’t seen a similar issue been mentioned in either the Known Issues part of the article or in the comments section. I’ve also tried searching around but haven’t found any similar reports.
Given this situation, could you please clarify the things below which might be helpful to narrow down the problem:
- Does this issue affect some particular users in your environment?
- Can the Outlook not responding issue be reproduced by some specific steps when using Outlook or it just occurs randomly?
- What’s the detailed build number of the affected Outlook clients? You can view the version information via File > Office Account > About Outlook.
In addition, if possible, it is recommended that you create a new Outlook profile and then use the new profile to replace the original profile see if the issue persists. You could also refer to this document Outlook crashes or stops responding when used with Office 365 - Microsoft Support to make some attempts.
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