text: Q:
  
  How to prevent Ubuntu One for Windows from automatically signing on to my account?
  
  I have an Ubuntu One account setup in 11.10. I've sync files and it works perfectly.
  However, at work, I can only use Windows OS, so I've installed U1 for Windows. The computer at work is a shared computer, thus I am trying to find ways how to keep my sync files safe from unauthorized access. 
  There are two issues that I'd like to fix:
  First: U1 automatically starts and connect upon boot.
  I have already unchecked the "Connect automatically when the computer starts" option from the Settings tab and rebooted several times, still U1 automatically starts on system boot and appears at the system try. This means that whoever logs into the computer can just click U1 from the system tray and access my files. 
  How do I resolve this?
  
  Second: U1 automatically signs on to my account.
  Even with the first issue resolved, my files are still vulnerable since U1 can be launched with just one click from the start menu which then automatically signs into my account without asking for a password (shown below).
  Is there a way to force U1 to prompt for a password?
  
  I know I could just setup a password to the sync folders in the Windows Explorer but what would prevent someone from accessing my files (those which I choose not to sync)? Since the U1 window automatically signs into my account, someone could just easily tick the "Syn locally?" box and access the files.
  
  Or I'd be better off accessing the files from the browser - downloading them and uploading (again) - than syncing them?
  
  A:
  
  There is currently no easy way of doing what you want to do. Also, I need to point out that even when the Ubuntu One syncdaemon is not running, the files of the folders you've selected will still be present and anybody with access to the machine will be able to inspect them, and any changes made to the files while syncdaemon is not running will be synchronized up the server as soon as it starts.
  Anyhow. You want to do two things: prevent Ubuntu One (both the syncdaemon and the control panel icon) from running automatically, and, remove the credentials so the login isn't automatic when it is run.
  The first is a little bit fiddly, but you only need to do it once: run regedit, and under HKEY_CURRENT_USER look for Software\Microsoft\Windows\CurrentVersion\Run. Remove both Ubuntu One and Ubuntu One Icon:
  
  Then, every time you log want to log out (and that's inconvenient, I know), you stop Ubuntu One, go to Control Panel/Credentials, expand the Ubuntu One entry, and remove it from the vault:
  
  HTH,
  
  A:
  
  Unfortunately, Ubuntu One is (naturally) based upon the strong one-user-per-account model of Ubuntu/Linux, which it carries over to Windows. It assumes that since only you would be able to log in to your Windows account, it's safe to not ask you for a password every time.
  The only solution appears to make your Windows login process similar to what you do on Ubuntu - require a password, no auto-login, each regular user of the computer gets his/her own account, guests use a special "guest" account.
  I would file a "wishlist" bug for this though, it would certainly be a helpful feature to have - I can see many folks (especially those with "family" computers) wanting the stronger "two-factor"-style authentication of having to log into Ubuntu One also each time it is started.
  
  