How to Clear the Outlook Cache

Option 1

Try this first by following the instructions in Microsoft's help article here:

https://learn.microsoft.com/en-us/office/dev/add-ins/testing/clear-cache#new-outlook-on-windows

Option 2 (Administrator access required)

Press the Windows key on your keyboard.

In the Start menu pop-up, type cmd  

Click Run as administrator.

If prompted to allow it, click YES.

In the terminal window, type this:

olk.exe /clearcache