Thanks for the suggestion.DanFisherman supported this idea ·DanFisherman commented
Folks, I have been using OneDrive on an external drive since FOREVER on a Mac. I am not sure why you aren't able to do this. All I have to say is this. Try to fix your Read&Write permissions on the external. Or create a folder, called say OneDrive, and inside of it, select it as your onedrive folder. OneDrive app will move your OneDrive folder from its current location into that external hard drive. It would look like this: ExtHDD>OneDrive>OneDrive> and that should solve it.