I am on 10.10 and u1sdtool seems to be completely broken. I reinstalled it, no change. I can add my PC to the account, but it is added twice(!) every time I tried. So I have my netbook and two times my PC in the account. The netbook with 10.04 has no problems.
Below is the error msg I get when attempting to startup Ubuntu One on the command line.
desktop:~$ u1sdtool --status
Oops, an error ocurred: Traceback (most recent call last): Failure: dbus.exceptions.DBusException: org.freedesktop.DBus.Error.NoReply: Did not receive a reply. Possible causes include: the remote application did not send a reply, the message bus security policy blocked the reply, the reply timeout expired, or the network connection was broken. desktop:~$
Starting it from the Me Menu has the same effect, the HDD will get really busy for a minute and then nothing happens, the client will not start.
Nothing in the syslog or anywhere.