I get Authentication is needed to run `/usr/bin/dropbox' as the super user
Solution 1:
Find where your dropbox executable is using the following command:
which dropbox
This will show you the actual filepath of the dropbox executable file. In most cases, it will be /usr/bin/dropbox. Open it with your preferred editor:
sudo vi /usr/bin/dropbox
Find the following line and change
PARENT_DIR = os.path.expanduser("/var/lib/dropbox")
to
PARENT_DIR = os.path.expanduser("~")
This will direct Dropbox to access your Home folder for the config files. Save and restart dropbox:
dropbox start -i
Further explanations