Make sure you have upgraded to the latest version of Dropbox which can be found here.
Keep the Dropbox folder in the default location, not in the Desktop or Documents folders. If Dropbox has been moved to the Desktop or Documents folder, and these are being synced by iCloud, you may experience confusing sync icons on Dropbox. Instructions for moving your Dropbox folder back to its default location can be found here.
Manage iCloud warning notifications by using the following steps:
- Open Finder.
- Open Finder Preferences.
- Click Advanced.
- Uncheck Show warning before removing form iCloud Drive.
- Note: Disabling iCloud notifications will not remove the conflicting sync icons.
Update your Accessibility permissions, if needed. Information and instructions on updating your Accessibility permissions for Dropbox can be found here.
The Dropbox Help Center has provided more detailed information on this issue which is available here: https://www.dropbox.com/help/9269#disable