Autosave UI is HORRENDOUS
Right now you have an "autosave" toggle on the Excel header. But this is set to "off" and is not able to be toggled on, unless you are working with a file on one drive. How presumptuous of MSFT - you put a control on the interface with no way to address it. And, your support is clueless (initially) as to why this is usable. Because they have all been trained to think that everyone uses everything you create all the time.
Or organization, like so many others, relies on Dropbox. I also use iCloud. And Box. And OneDrive. But my corporate standard is Dropbox. In preferences the autosave is turned on, BUT. IT. DOES. NOT. WORK. Lost both excel spreadsheets and powerpoint changes where I expected that the autosave would help me. Apparently, you don't have a very large test matrix.
You should only make features visible if the right back end was enabled. How can you let users think they are both protected (autosave clicked in preferences) and also NOT protected (toggle is unable to be clicked in product UI)?
This is a horrendous user interface mess. Please fix.