This package is not installed:
aptitude search libtachyon
p libtachyon-0.99 - Parallel/Multiprocessor Ray Tracing Software, shared library 
p libtachyon-0.99:i386 - Parallel/Multiprocessor Ray Tracing Software, shared library 
p libtachyon-dev - Parallel/Multiprocessor Ray Tracing Software, development files 
p libtachyon-dev:i386 - Parallel/Multiprocessor Ray Tracing Software, development files 

but:
aptitude show libtachyon-0.99
Пакет: libtachyon-0.99 
Новый: да
Состояние: не установлен
Версия: 0.99~b2+dfsg-0.3
Приоритет: необязательный
Раздел: universe/libs
Сопровождающий: Ubuntu Developers <email address hidden>
Архитектура: amd64
Размер в распакованном виде: 238 k
Зависимости: libc6 (>= 2.7)
Конфликтует: libtachyon-0.99
Описание: Parallel/Multiprocessor Ray Tracing Software, shared library
 Tachyon is a portable, high performance parallel ray tracing system supporting MPI and multithreaded implementations. Tachyon is built as a C callable library, which
 can be used with the included demo programs or within your own application. The distribution also includes a simple scene file parser front-end which reads a few
 different formats. 
 
 Tachyon implements all of the basic geometric primitives such as triangles, planes, spheres, cylinders, etc. Some of the goals in developing Tachyon were to make it
 fast and for it to parallelize well. These are what set it apart from more full-featured programs like POV-Ray, Rayshade, and others. Tachyon supports enough features
 to be an excellent alternative to slower programs for demanding animation and scientific visualization tasks. As time goes on, Tachyon will indeed incorporate more
 features, but with a continued emphasis on rendering performance.

The selected with bold font string "Конфликтует: libtachyon-0.99" may be readed that "conflicted: libtachyon-0.99"
The question: How not installed package may conflict with self?


Tue, 10 Apr 2012 21:19:42 -0000 от Brian Murray <email address hidden>:
> It's odd that the Priority is 'optiolal'. Are you using a non-Ubuntu
> version of libtachyon-0.99?
> 
> -- 
> You received this bug notification because you are subscribed to the bug
> report.
> https://bugs.launchpad.net/bugs/952723
> 
> Title:
> update-manager crashed with KeyError in __getitem__():
> 'libtachyon-0.99\x08Priority: optiolal' dist-upgrade
> 
> Status in “update-manager” package in Ubuntu:
> Confirmed
> 
> Bug description:
> Ubuntu 12.04 (precise)
> 
> Пакет: update-manager 
> Состояние: установлен
> Автоматически установлен: нет
> Версия: 1:0.156.7
> Приоритет: необязательный
> Раздел: gnome
> Сопровождающий: Michael Vogt <email address hidden>
> Размер в распакованном виде: 1 415 k
> Зависимости: python2.7, python (>= 2.7.1-0ubuntu2), python (< 2.8), dconf-gsettings-backend | gsettings-backend, update-manager-core (= 1:0.156.7),
> python-aptdaemon.gtk3widgets (>= 0.40) | synaptic, python-dbus, python-gobject (>= 2.28.6-2), gir1.2-vte-2.90, gir1.2-gtk-3.0
> Рекомендует: software-properties-gtk (>= 0.71.2), gir1.2-dbusmenu-gtk-0.4, gir1.2-unity-5.0, gir1.2-webkit-3.0
> Описание: GNOME application that manages apt updates
> This is the GNOME apt update manager. It checks for updates and lets the user choose which to install.
> 
> Update-manager crached always with start or load updating information
> 
> ProblemType: Crash
> DistroRelease: Ubuntu 12.04
> Package: update-manager 1:0.156.7
> ProcVersionSignature: Ubuntu 3.2.0-18.28-generic 3.2.9
> Uname: Linux 3.2.0-18-generic x86_64
> ApportVersion: 1.94-0ubuntu2
> Architecture: amd64
> CrashCounter: 1
> Date: Mon Mar 12 08:30:22 2012
> ExecutablePath: /usr/bin/update-manager
> GsettingsChanges:
> com.ubuntu.update-manager first-run false
> com.ubuntu.update-manager launch-time 1331526631
> com.ubuntu.update-manager show-details true
> com.ubuntu.update-manager window-height 600
> com.ubuntu.update-manager window-width 841
> InstallationMedia: Ubuntu 10.10 "Maverick Meerkat" - Release amd64 (20101007.1)
> InterpreterPath: /usr/bin/python2.7
> PackageArchitecture: all
> ProcCmdline: /usr/bin/python /usr/bin/update-manager
> ProcEnviron:
> SHELL=/bin/bash
> PATH=(custom, no user)
> LANG=ru_RU.UTF-8
> PythonArgs: ['/usr/bin/update-manager']
> SourcePackage: update-manager
> Title: update-manager crashed with KeyError in __getitem__(): 'libtachyon-0.99\x08Priority: optiolal'
> UpgradeStatus: Upgraded to precise on 2012-03-07 (4 days ago)
> UserGroups: adm admin cdrom dialout lpadmin plugdev sambashare www-data
> 
> To manage notifications about this bug go to:
> https://bugs.launchpad.net/ubuntu/+source/update-manager/+bug/952723/+subscriptions
>