Using Classic Outlook on Windows for personal email, calendar, and contact management
I would recommend updating back to the latest version (File, Office Account, Update Options, Update Now). If you are seeing the tiny font bug in the reading pane just restart Outlook a couple times to clear that up.
If permissions are restricted on Temp then I agree that you should fix that next to continue troubleshooting. This is how it looks on my machine. If you cannot add or edit then maybe try Disable Inheritance and convert permissions to explicit and then add at least what I have below.