Tiago, something did not go as planned. sudo apt-get update ... Get:1 http://downloads.skewed.de precise Release.gpg [490 B] Hit http://security.ubuntu.com precise-security/universe Translation-en Get:2 http://downloads.skewed.de precise Release [2,436 B] Get:3 http://downloads.skewed.de precise/universe Sources [1,074 B] Ign http://ppa.launchpad.net precise/main Translation-en_US Ign http://ppa.launchpad.net precise/main Translation-en Ign http://ppa.launchpad.net precise/main Translation-en_US Get:4 http://downloads.skewed.de precise/universe amd64 Packages [959 B] Get:5 http://downloads.skewed.de precise/universe i386 Packages [956 B] Ign http://downloads.skewed.de precise/universe TranslationIndex Ign http://ppa.launchpad.net precise/main Translation-en Ign http://ppa.launchpad.net precise/main Translation-en_US Ign http://ppa.launchpad.net precise/main Translation-en Ign http://downloads.skewed.de precise/universe Translation-en_US Ign http://downloads.skewed.de precise/universe Translation-en Fetched 5,915 B in 2s (2,333 B/s) Reading package lists... Done val@machine:~$ sudo apt-get install graph-tool Reading package lists... Done Building dependency tree Reading state information... 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: * graph-tool : Depends: libboost1.46-dev but it is not going to be installed* E: Unable to correct problems, you have held broken packages. It seems to request even an older version than before. I am on 1.49 now -- View this message in context: http://main-discussion-list-for-the-graph-tool-project.982480.n3.nabble.com/... Sent from the Main discussion list for the graph-tool project mailing list archive at Nabble.com.