Part of setting up a DEVONthink sync to Dropbox is making sure you don’t re-download the sync data unnecessarily. If you don’t exclude the DEVONthink Packet Sync folder in the Dropbox application on your Mac, it will download what our sync has just uploaded. This wastes bandwidth and space on your machine. It may also spam your machine with messages about files being changed.
The latest version of the Dropbox application has changed the location of this option. It is now found in the Dropbox application’s Preferences > Sync > Selective Sync. Press the button reading Choose folders to sync then uncheck the Apps/DEVONthink Packet Sync folder.