OneNote sync problem.
OneNote auto syncs and saves itself to OneDrive, but the file that it creates in the process (html file) is easily accessed in OneDrive and is easily deleted. If moved/ deleted, the sync process is disabled. If moved back the sync process is re-enabled and all of your content/ data in OneNote is reset and lost. This html file should be hidden in the drive or encrypted so that it isn't deleted by accident. This relates to OneNote app for Mac & iPhone, but may relate to others.