I've had the same problem on two different computers. On this laptop, installing ubuntuone-client-tools and logging out/back in worked. On my other PC, removing the Ubuntu One token from Passwords tab under Accessories > Passwords and Encryption Keys did the trick.
I've had the same problem on two different computers. On this laptop, installing ubuntuone- client- tools and logging out/back in worked. On my other PC, removing the Ubuntu One token from Passwords tab under Accessories > Passwords and Encryption Keys did the trick.