Force Outlook not to create .olk15_messages?

Question

macOS

For some reason, Outlook is constantly backing up emails to disk in
/Users/$username/Library/Group Containers/UBF8T346G9.Office/Outlook/Outlook 15 Profiles/Main Profile/Data/Messages/
as .olk15_messages files for each email.
All letters are stored on the exchange server by default, so a local backup is not needed. Which also eats up space significantly (in my case, more than 20GB)
Does anyone know how to configure Outlook to no longer backup letters?

Answer 1

I don't have such files, maybe it's a server problem? You should contact Support MS