Fixing missing or unmet dependencies on Ubuntu
Installing packages from other repositories may understand that some dependencies are missing in upgrading other packages.
Below, for example, is an attempt to upgrade the libcurl3-gnutls package but the installed version collides with other, older packages and thus is not upgradeable.
Specifically, a library named libgnutls30, for the system, already appears to be updated to the latest release, but from the package one would like to upgrade, a higher version is required.
Issue Output:
apt-get upgrade libcurl3-gnutls
Reading package lists… Done
Building dependency tree
Reading state information… Done
Calculating upgrade… Done
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:
The following packages have unmet dependencies:
libcurl3-gnutls : Depends: libgnutls30 (>= 3.7.2) but 3.6.13-2ubuntu1.6 is to be installed
Depends: libnettle8 but it is not installable
E: Broken packages
How to fix it
dpkg –force-all –configure -a
dpkg –purge –force-depends libcurl3-gnutls
apt –fix-broken install
apt-get -f install
apt autoremove