Comment 11 for bug 776386

@Guillermo: Thanks for the quick reply. My problem is not related to the HDD. I currently have zero bad sectors and zero reallocated sectors.

After following instructions for complete purging and re-installation of ubuntu one, the issue remains...without any files to sync locally, having removed them to rule out any local file problems. I followed joshuahoover's instructions:

    Quit the Ubuntu One client
    $ sudo rm -rf ~/.share/local/ubuntuone
    $ rm -rf ~/.cache/ubuntuone
    $ rm -rf ~/.config/ubuntuone
    $ mv ~/Ubuntu\ One/ ~/Ubuntu\ One_old/
    Open Applications->Accessories->Passwords and Encryption Keys, go to the Passwords tab, delete the Ubuntu One token
    $ sudo apt-get purge ubuntuone*
    $ sudo apt-get install ubuntuone*
    Open Applications->Internet->Ubuntu One and you should have to add your computer via the web page that comes up once you login to Ubuntu One
    Put a small text file in the newly created ~/Ubuntu One/ directory and make sure that syncs correctly, if not, please report a bug
    If all goes well this far, move the files and folders from ~/Ubuntu One_old/ to ~/Ubuntu One/ and the sync should happen

Never got to the last two steps. Immediately on signing into the new U1 client applet, I get the error:

File Sync error. (org.freedesktop.DBus.Error.NoReply: Message did not receive a reply (timeout by message bus))

and nautilus is hung, and CPU is 100% until session is terminated. Simply having Ubuntu One ticked in Startup Applications causes this behavior at login. The only way for me to have a useable session is to disable U1 entirely.