The following packages have unmet dependencies!

You can install the package using.

make sure the repo sources are up to date

sudo apt-get update

To Install the package.

sudo apt-get install packagename

Once the package determines that you have some missing dependencies, run the following command to fix broken or missing dependencies.

sudo apt-get install -f

Above command will only download the missing dependencies if you have already installed the package.

I know I'm a bit late, but none of the above solutions worked for me. What really solved my problem was to use aptitude instead of apt-get. aptitude will suggest resolutions to the problem.

Simply run these:

sudo apt-get install aptitude

sudo aptitude install <package-name>

aptitude will suggest dependencies resolution for you e.g:

The following actions will resolve these dependencies:

Keep the following packages at their current version:
1)     libyaml-dev [Not Installed]                        

Accept this solution? [Y/n/q/? (n)

The following actions will resolve these dependencies:

Downgrade the following packages:                                
1)     libyaml-0-2 [0.1.4-3ubuntu3.1 (now) -> 0.1.4-3ubuntu3 (trusty)]

Accept this solution? [Y/n/q/?] (Y)

as discussed in this post.

Sometimes the dependencies that need fixing are unrelated to the program you are trying to install. In my case it was giving off this error:

The following have unmet dependecies

shashlik : Depends: libc6-i386 but it is not going to be installed

Depends: lib32gcc1 but it is not going to be installed

Depends: lib32z1 but it is not going to be installed

It turned out that I had tried to install a program called "Shashlik" and the installation had failed. So I ran the code:

sudo apt-get --purge remove shashlik

And then I ran:

sudo apt install autoconf

This seemed to fix the error as my program then installed. I am not sure how much the second command helped but I put it there in case it was necessary for the solution to work.