I'm using Outline on my iMac and iPad. I'm syncing through Dropbox and have no problem at all, works perfect. The problem is that I want to use Outline on my MacBook Air and there is where trouble starts. It's not possible to open an existing .one file from the Dropbox folder. The error message "Not a OneNote Notebook" pops up. Huh...I'm using this .one not file on my iMac and there's no problem at all. The option I'm using for opening a .one file is; Open from Mac.
What's the problem? Does anyone have a clue?