It might be that your
/boot partition has accumulated too many kernel versions while doing upgrades over time. This partition is likely to be separate from your large disk partition (mounted as
/). You can check the
/boot partition space like this (look for the line with /boot):
There is a nice page on how to remove old kernels.
In short, check your current kernel version, get the list of what is installed, and then apt-get remove the old versions. There is also a "magic" one-liner command on the page that will do all that for you. But use it at your own risk.
Instructions in more detail:
Get the current kernel version, the one you want to keep:
Get the list of all kernels installed:
dpkg -l | grep linux-image-
Run apt-get remove on the kernels you want to remove. Not on the latest one! For example:
sudo apt-get remove linux-image-2.6.32-22-generic
dpkg -l will tell you the status of the (kernel) package before the package name.
rc linux-image-3.13.0-39-generic ...
ii linux-image-3.13.0-40-generic ...
- "rc" means that the package is removed and has configuration files. These you do not need to remove any more.
- "ii" means that the package is marked for installation and is installed
Based on this, you could list only the kernel packages that are installed:
dpkg -l | grep "ii.*linux-image-"
Alternative solution, using GUI tool Ubuntu Tweak.
Install and go to Computer Janitor, check the System->Old Kernel and System->Unneeded packages, and press Clean.