I don't know how you upgraded from 14.04.3 to 15.10 but sounds like you took a shortcut and those are not supported
** Changed in: mesa (Ubuntu) Status: New => Invalid -- You received this bug notification because you are a member of Desktop Packages, which is subscribed to mesa in Ubuntu. https://bugs.launchpad.net/bugs/1531647 Title: Dependency hell: "libgl1-mesa-dri-lts-vivid : Conflicts: libgl1-mesa- dri" Status in mesa package in Ubuntu: Invalid Bug description: I'm not entirely sure whether it's package updates or something I did that caused this problem, but I'm getting this: $ sudo aptitude dist-upgrade The following NEW packages will be installed: libgl1-mesa-dri{a} libllvm3.6v5{ab} libxatracker2{a} xserver-xorg{a} xserver-xorg-core{a} xserver-xorg-video-all{a} xserver-xorg-video-ati{a} xserver-xorg-video-cirrus{a} xserver-xorg-video-fbdev{a} xserver-xorg-video-intel{a} xserver-xorg-video-mach64{a} xserver-xorg-video-mga{a} xserver-xorg-video-neomagic{a} xserver-xorg-video-nouveau{a} xserver-xorg-video-openchrome{a} xserver-xorg-video-qxl{a} xserver-xorg-video-r128{a} xserver-xorg-video-radeon{a} xserver-xorg-video-savage{a} xserver-xorg-video-siliconmotion{a} xserver-xorg-video-sisusb{a} xserver-xorg-video-tdfx{a} xserver-xorg-video-trident{a} xserver-xorg-video-vesa{a} xserver-xorg-video-vmware{a} The following packages will be upgraded: libgbm1 xorg 2 packages upgraded, 25 newly installed, 0 to remove and 0 not upgraded. Need to get 16.5 MB of archives. After unpacking 139 MB will be used. The following packages have unmet dependencies: libgl1-mesa-dri-lts-vivid : Conflicts: libgl1-mesa-dri but 11.0.2-1ubuntu4 is to be installed. xserver-xorg-lts-vivid : Conflicts: libgl1-mesa-dri (>= 0~) but 11.0.2-1ubuntu4 is to be installed. Conflicts: libxatracker2 (>= 0~) but 11.0.2-1ubuntu4 is to be installed. Conflicts: xserver-xorg but 1:7.7+7ubuntu4 is to be installed. Conflicts: xserver-xorg-core (>= 0~) but 2:1.17.2-1ubuntu9.1 is to be installed. Conflicts: xserver-xorg-video-all (>= 0~) but 1:7.7+7ubuntu4 is to be installed. libllvm3.6v5 : Conflicts: libllvm3.6 but 1:3.6-2ubuntu1 is installed. xserver-xorg-core-lts-vivid : Conflicts: xserver-xorg-core but 2:1.17.2-1ubuntu9.1 is to be installed. Conflicts: xserver-xorg-video-modesetting which is a virtual package, provided by: - xserver-xorg-core, but 2:1.17.2-1ubuntu9.1 is to be installed. - xserver-xorg-core, but 2:1.17.2-1ubuntu9.1 is to be installed. The following actions will resolve these dependencies: <a series of absurd attempts to resolve the conflict follow> Not sure how to proceed. Thanks! I'm running Ubuntu 15.10. $ ubuntu-bug mesa # gives "The problem cannot be reported: \ The report belongs to a package that is not installed." $ dpkg -l | grep -e mesa -e xorg ii libegl1-mesa-lts-vivid:amd64 10.5.9-2ubuntu1~trusty2 amd64 free implementation of the EGL API -- runtime ii libgl1-mesa-dri-lts-vivid:amd64 10.5.9-2ubuntu1~trusty2 amd64 free implementation of the OpenGL API -- DRI modules ii libgl1-mesa-glx-lts-vivid:amd64 10.5.9-2ubuntu1~trusty2 amd64 free implementation of the OpenGL API -- GLX runtime ii libglapi-mesa-lts-vivid:amd64 10.5.9-2ubuntu1~trusty2 amd64 free implementation of the GL API -- shared library rc libgles1-mesa-lts-vivid:amd64 10.5.9-2ubuntu1~trusty2 amd64 free implementation of the OpenGL|ES 1.x API -- runtime rc libgles2-mesa-lts-vivid:amd64 10.5.9-2ubuntu1~trusty2 amd64 free implementation of the OpenGL|ES 2.x API -- runtime ii libglu1-mesa:amd64 9.0.0-2 amd64 Mesa OpenGL utility library (GLU) ii libwayland-egl1-mesa-lts-vivid:amd64 10.5.9-2ubuntu1~trusty2 amd64 implementation of the Wayland EGL platform -- runtime ii mesa-utils 8.2.0-1ubuntu1 amd64 Miscellaneous Mesa GL utilities rc mir-client-platform-mesa2:amd64 0.12.1+15.04.20150324-0ubuntu1 amd64 Display server for Ubuntu - client platform library for Mesa ii python3-xkit 0.5.0ubuntu2 all library for the manipulation of xorg.conf files (Python 3) ii xorg 1:7.7+1ubuntu8.1 amd64 X.Org X Window System ii xorg-docs-core 1:1.7.1-0ubuntu1 all Core documentation for the X.org X Window System ii xserver-xorg-core-lts-vivid 2:1.17.1-0ubuntu3.1~trusty1 amd64 Xorg X server - core server ii xserver-xorg-input-evdev-lts-vivid 1:2.9.0-1ubuntu2~trusty1 amd64 X.Org X server -- evdev input driver ii xserver-xorg-lts-vivid 1:7.7+7ubuntu3~trusty1 amd64 X.Org X server rc xserver-xorg-video-intel-lts-vivid 2:2.99.917-1~exp1ubuntu2.2~trusty1 amd64 X.Org X server -- Intel i8xx, i9xx display driver rc xserver-xorg-video-openchrome-lts-vivid 1:0.3.3-1ubuntu1~trusty1 amd64 X.Org X server -- VIA display driver rc xserver-xorg-video-vmware-lts-vivid 1:13.1.0-0ubuntu1build1~trusty1 amd64 X.Org X server -- VMware display driver To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/mesa/+bug/1531647/+subscriptions -- Mailing list: https://launchpad.net/~desktop-packages Post to : desktop-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~desktop-packages More help : https://help.launchpad.net/ListHelp