Co-Authoring in PowerPoint for Mac - Constant issues merging changes

Maybe a conflict with the OneDrive client? It should be opening direct from the web location thou by default. Maybe have your users try to open the files from the web location using "Edit in powerpoint" option instead, if they aren't already doing it that way? See if that helps. Guess Pausing OneDrive sync might be an option, but obviously it shouldn't work that way, just thinking of some work arounds for now :).