Ubuntu 13.10 has been launched and now users are reporting various problems, including one with the Dropbox client.You can install Dropbox either from Ubuntu Software Center or from the deb file provided by the developers, but it makes no difference.
Even if the installation goes smoothly, with either method, users don't have access to the GUI, and the indicator that is normally displayed is missing.
Most likely it's a problem with Dropbox and the new version of Unity that doesn't accept the proper indicator. This can be a problem because users won't have access to the settings panel.
The background sync with the Dropbox service works and the folders do get updated, but it's a gratuitous issue that needs to be resolved soon.
Users had other problems with Dropbox before the launch of Ubuntu 13.10 when it crashed Files (Nautilus). The problem was fixed with an update and we expect the same to happen with this issue.
A reader has pointed out that there is a simple solution to this problem. Just run this command and then log out and log it:
sudo apt-get install libappindicator1