Ubuntu One used to work well on my Windows 7 machine. Last week after opening it I received a message asking me if I wanted to upgrade to a newer version. I accepted and the upgrade installed. Now the program doesn't load at all. I have tried uninstalling and re-installing without success. Can you please help as I use it on my Windows 7 and Ubuntu machines as well as an Android device.
I had the same problem and had to roll back the update. The UbuntuOne folder in Program Files had a rollbackBackupDirectory. I first had to terminate the running processes. I then renamed the upgraded UbuntuOne folder to UbuntuOne_Old and restored the backup to the UbuntuOne folder. After restarting the machine the old version of UbuntuOne was running and working again.