Outlook slow when using shared calendars

Applies to: Microsoft Outlook 2013, 2016, 2019

Symptoms

When you open a shared calendar, Outlook takes a long time to display the results.

Solution

Turn off public folder caching:

1. In Outlook choose File > Account Settings > Account Settings
2. In the Email dialog select your main email account, then Change...
3. Select More Settings... > Advanced tab
4. Uncheck Download shared folders