Co-authoring not working on Word for Mac

[New Daddy]

Co-authoring - including simultaneous editing - works perfectly on my Word for Windows with Onedrive for Business.

But my Word for Mac doesn't recognize shared files and doesn't enter co-authoring, even with documents stored on Onedrive for Mac (which is equivalent to Onedrive for Business for Windows.)

Does anyone have any idea why?

This is a huge block to my planned complete transition to Mac.

[HansV]

Which version of Office for Mac do you have?

[New Daddy]

Which version of Office for Mac do you have?

It says Version 15.31 (170216). I believe it's Word 2016, as my firm deploys the 2016 version for Windows.

[HansV]

As far as I know, coauthoring should work in Word 2016 for Mac too, but since I don't have a Mac I cannot check that of course.

[New Daddy]

I'm just responding to my own question for posterity's sake.

It turns out that I can't co-author a document in a Onedrive for Business folder until I save it to the cloud, again.

That is, while I may have a document in my iMac's Onedrive for Business folder that represents the same file in my Windows PC's Onedrive for Business folder that I've been co-authoring, I still have to open the document in my iMac's Onedrive for Business folder and save it again to the Onedrive for Business cloud.

Because the document will still end up in the Onedrive for Business folder, the folder structure doesn't change at all.

But once this has been done, the file becomes available for co-authoring.

Very weird and complicated but I'm getting the hang of it.