I needed to uninstall firefox 19 which was installed during the installation of Ubuntu 12.04, in order to downgrade the version so that I could install firefox add-on compatible to lower versions. But now my system's broken.
I tried to update, or upgrade,
apt-get -f install, synaptic installation, or re-install firefox,... but to no avail. Terminal error reports:
sudo apt-get -f install Reading package lists... Done Building dependency tree Reading state information... Done Correcting dependencies... Done The following package was automatically installed and is no longer required: python-zope.app.content Use 'apt-get autoremove' to remove them. The following extra packages will be installed: firefox firefox-globalmenu Suggested packages: latex-xft-fonts firefox-gnome-support The following NEW packages will be installed: firefox The following packages will be upgraded: firefox-globalmenu 1 upgraded, 1 newly installed, 0 to remove and 9 not upgraded. 1 not fully installed or removed. Need to get 0 B/25.6 MB of archives. After this operation, 52.7 MB of additional disk space will be used. Do you want to continue [Y/n]? y (Reading database ... 299890 files and directories currently installed.) Unpacking firefox (from .../firefox_20.0~b1+build2-0ubuntu0.12.04.1~mfn3_i386.deb) ... dpkg: error processing /var/cache/apt/archives/firefox_20.0~b1+build2-0ubuntu0.12.04.1~mfn3_i386.deb (--unpack): trying to overwrite '/usr/lib/firefox/plugins', which is also in package google-talkplugin 188.8.131.52-1 Processing triggers for bamfdaemon ... Rebuilding /usr/share/applications/bamf.index... Processing triggers for desktop-file-utils ... Processing triggers for gnome-menus ... Processing triggers for man-db ... Errors were encountered while processing: /var/cache/apt/archives/firefox_20.0~b1+build2-0ubuntu0.12.04.1~mfn3_i386.deb E: Sub-process /usr/bin/dpkg returned an error code (1)
How can I fix this?