@FuzMic - the problem is that cloud storage uses whole-file transfer protocols, but Access derives its sharing from the Windows File and Printer Sharing protocol called Server Message Block (SMB) - which is a way to share a PART of a file. Cloud servers almost NEVER recognize SMB requests coming in. However, the specific danger is that even if they DO recognize a partial-file request, the cloud connections tend to be unstable. If you were writing back a part of a file to a cloud file and the connection broke, what do you think would happen to that partially updated Access file? (That was a rhetorical question... answer: It would become corrupted and unusable.)
I suppose you COULD try it - but the risk factors lean VERY HEAVILY towards corruption - within a matter of hours or days.