This suddenly happened to me today after I upgraded my Unity (Ubuntu 14.04 LTS) via Software Updater. I got a warning telling me that I have installed packages that unmet dependencies.
I used Synaptic and use 'Fix Broken Package' but I get this error (I used
apt-get -f install on terminal and get the same result):
E: /var/cache/apt/archives/liblwgeom-2.1.8_2.1.8+dfsg-1.pgdg14.04+1_amd64.deb: trying to overwrite '/usr/lib/liblwgeom-2.1.8.so', which is also in package liblwgeom-2.1.7 2.1.8+dfsg-1~95.git18216c0.pgdg14.04+1
I installed my postgres and postgis package from ppa http://apt.postgresql.org/pub/repos/apt . Never had any problem until today.
I've searched on the internet and tried the recommendations I found:
apt-get update and
apt-get upgrade, also
dpkg --configure -a but none works for me.
I'm new in using Ubuntu and would very appreciate of your help here.