When working with Outlook for Mac the content of email messages are rendered in a web browser control that is specific to Outlook (it does not use Safari). So when you have a need to clear any cached data or cookies it is far from obvious how you should go about clearing this cache. I’m a newbie to Mac so maybe this is obvious to seasoned users! Here’s how I went about it.
- Start the Finder application
- Open the Go menu
- You need to get to the hidden Library folder. To get the Library folder to show up under the go menu, hold down the option button on your keyboard
- Now open the Library folder
- Find the Containers folder under Library and expand it
- You should be able to find a folder called com.Microsoft.OsfWebHost
- To clear out the web browser cache I move the following to the trash:
- com.Microsoft.OsfWebHost/Library/Caches/com.Microsoft.OsfWebHost (folder)
- com.Microsoft.OsfWebHost/Library/Caches/Cookies/Cookies.binarycookies (file)
Restart Outlook and you should now have no cached files being used.
Cameron Dwyer 
I do not have any folder titled com.microsoft.osfWebHost in my Containers folder.
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