content: Issues 1. The .one file extension is not registered with the OS. 2. No option to open a file anywhere in the file system. 3. Related. No option in OneDrive to upload a file anywhere in the file system. 4. If you try to open a file in the Downloads folder you get a message about not having an app to read the file. I exported a couple OneNote pages end emailed them from my work account to my Gmail account. So far I have not been able to open them locally or upload them to OneDrive .