OneDrive For Business
Sync an external drive
Luke Nelson commented
Duplicate of this issue with many more votes: https://onedrive.uservoice.com/forums/913525-onedrive-on-mac/suggestions/11170029-allow-the-mac-version-to-install-onedrive-folder-a
This is the only reason I keep my Google Drive.
The lack of the ability to sync to an external drive makes this product ... unusable really.
That's really quite an oversight.
Thankfully Dropbox is available to fill the breach.