How to Clear Outlook Shared Calendar Cache

1. Right-click the specific calendar, and then click Properties.
2. Click Clear Offline Items, and then click OK.
3. Click the Send/Receive tab on the Ribbon and click Update Folder.

Then Select “Clear Offline Items”

Recommendation

We would also recommend only opening Calendars when needed and unchecking when not to minimise the chances of corruption in the cache. This will also help to speed out Outlooks response time both under normal use, and when flicking between Email etc and Calendars.

Ref:Tessellate OS Support – Clear Outlook Shared Calendar Cache