This question already has an answer here:
I got an error icon above my menu bar. When I click on it I get three options with some details. It says
An error occurred please run package manager from the right-click menu or apt-get in terminal to see what's wrong. The error message was: 'Error:brokencount>0'. This usually means that your installed packages have unmet dependencies"
apt-get in terminal, with commands and options it says
See the apt-get(8), sources.list(5) and apt.conf(5) manual pages for more information and options. This APT has Super Cow Powers.
When I tried to update my system it failed to update and showed this error message:
The package is broken The following packages have unmet dependencies: steam-launcher: Depends: curl but it is not installed Depends: jockey-common but it is not installed Depends: libc6 (>= 2.15) but 2.15-0ubuntu20 is installed