Dropbox won't be able to sync to external drives on macOS
An update to macOS and how Apple's File Provider API works will soon force apps like Dropbox to end support for external drives.

Dropbox losing functionality on macOS
Some Dropbox users have encountered issues with their external drive setup on Macs running macOS Ventura. This is due to a change to Apple's File Provider API that will require cloud storage providers to place system files within ~/Library/CloudStorage.
This Dropbox update has come as a surprise to users that rely upon local external storage for projects stored and synced with Dropbox. One user on the Dropbox forums describes the change as a "showstopper," stating the team will have to find a new service.
It isn't clear how this change will affect other third-party cloud storage providers. Any app that uses Apple's File Provider API will have to adopt the new system folder.
Dropbox shared the following details about how Apple's API changes affect users.
Read on AppleInsider

Dropbox losing functionality on macOS
Some Dropbox users have encountered issues with their external drive setup on Macs running macOS Ventura. This is due to a change to Apple's File Provider API that will require cloud storage providers to place system files within ~/Library/CloudStorage.
This Dropbox update has come as a surprise to users that rely upon local external storage for projects stored and synced with Dropbox. One user on the Dropbox forums describes the change as a "showstopper," stating the team will have to find a new service.
It isn't clear how this change will affect other third-party cloud storage providers. Any app that uses Apple's File Provider API will have to adopt the new system folder.
Dropbox shared the following details about how Apple's API changes affect users.
- Changing the location of your Dropbox folder is no longer supported by macOS.
- Due to the change of the Dropbox folder location, files that were previously linked in some third-party applications will need to be linked again.
- Storing your Dropbox folder on an external drive is no longer supported by macOS.
- Your Dropbox folder in Finder will now be found under Locations and no longer under Favorites.
- Individual folders can be moved from your Dropbox folder to Favorites for quick access.
Read on AppleInsider
Comments
The article is not detailed enough and requires us to make assumptions, which I don't like to do.
Is this talking exclusively about macOS Ventura? An OS version I happily have NOT upgraded to because I like Monterey better? :-)
Or will DropBox dump its awful new version onto us Monterey users too?
If the ticket to avoiding trouble is using Monterey, I am happy to stick with it. I strongly dislike the facelift of System Preferences in Ventura. Older is better.
Every 'upgrade' has me asking about possible quid pro quo and data scraping now - trust Apple - are you kidding...?
Maybe as a shareholder but as a customer...? Is Apple's MO to simply keep tightening the financial screws on customers ?
Embrace extend extinguish ? Should that be applied to Apple management ?
Welcome to the post Jobs world on the Mac...