Introduction I tried to upgrade my Ubuntu Server but it didn't boot up after rebooting. I jumped on via the console and saw the following: kernel panic-not syncing: VFS: unable to mount root fs on unknown block(0,0) I panicked and immediately feared the worse but turns out it is easy peasy to sort out. Fix The fix was pretty easy, I rebooted the box and used the advanced menu to look for an older kernel that I could boot into. There was so I tried the next available and it worked. I then used  the following command to see what the status of the /boot partition: df The answer was obvious: Filesystem     1K-blocks     Used    Available   Use%    Mounted on /dev/sda1     240972     240972     0    100%     /boot No space left! It was a simple case of running the following command: sudo apt-get autoremove The definition of which is "autoremove - Remove automatically all unused packages" This then freed up lots of space and I was able to upgrade again. /dev/sda1     240972     39506     189025     18%     /boot If you want to view what linux images are installed, use the following: dpkg --get-selections | grep linux-image- You'll get a similar result like below: linux-image-3.13.0-32-generic deinstall linux-image-3.13.0-44-generic deinstall linux-image-3.13.0-46-generic deinstall linux-image-3.13.0-48-generic deinstall linux-image-3.13.0-49-generic deinstall linux-image-3.13.0-51-generic deinstall linux-image-3.13.0-52-generic install linux-image-extra-3.13.0-32-generic deinstall linux-image-extra-3.13.0-44-generic deinstall linux-image-extra-3.13.0-46-generic deinstall linux-image-extra-3.13.0-48-generic deinstall linux-image-extra-3.13.0-49-generic deinstall linux-image-extra-3.13.0-51-generic deinstall linux-image-extra-3.13.0-52-generic install Job done.