A Microsoft file hosting and synchronization service.
not sure what you mean - I don't have an On / Off switch under "Files On Demand".
these are the settings on Device A.
On Device B, since making the post, I have selected "Free up disk space" on all files at the highest folder level, in the hope that that will fix it.
Ultimately, I agree, it should not be based on which device has the downloaded file, but should maintain the most recent file from the Sharepoint server.