Today I opened my Ubuntu and I saw
What should I do ?
Lets check the file system to make sure there aren't any errors.
sudo fsck -f /rebootTo check the hard disk for hardware errors...
Try UbuntuDisks application from the Unity dashboardSMART Data & TestsIf this doesn't help, you're going to need to reinstall Ubuntu. Boot the Ubuntu Live DVD and choose Install Ubuntu. Choose reinstall, and make sure to uncheck the format partition selection, and it'll keep your existing /home directory.