Office 365 / Chromebook file incompatibility?

Hi Max,

This seems to be a problem with accessing Word files while offline. Online, through OneDrive, I can access and edit old files, or create and edit new ones. But whether or not I'm online, if I store a file locally for offline use my only option is Word 365. And regardless of whether I navigate to a file from my Chromebook's "Files" tab or from within the app, I get "Read Only: You Can't Save Changes." So it appears to be impossible to use Word 365 (except as a reader), and therefore impossible to edit and re-save a Word file while offline. 

(Initially I thought this was a .doc v .docx problem, as I had some old files that had to be updated first. But both updated files and newer docx. files do the same thing.)

Everything I'd read indicated both that Word 365 was now fully compatible with (newer) Chromebooks. But I'm not seeing it - and, if true, that means there is no way to interact at all with a Word file on a Chromebook while offline.

(Just to test, I downloaded 365 onto my Android phone, where it works fine and I never get that Read-Only message.)   

Any illumination gratefully received.