Most likely your hard disk is failing, though it could possibly be a corrupt filesystem. You will need to check your syslog for more detailed error messages and should check the SMART health of the drive in the disks utility. If it is failing, you will need to replace it.
Most likely your hard disk is failing, though it could possibly be a corrupt filesystem. You will need to check your syslog for more detailed error messages and should check the SMART health of the drive in the disks utility. If it is failing, you will need to replace it.