I am running unity-2d in a LTSP thin client environment, on Precise, which requires unity-2d.
Today I upgraded packages, and ended up with unity-2d gone.
/var/log/apt/history.log says:
Start-Date: 2014-01-08 10:28:30
Commandline: apt-get dist-upgrade
Install: linux-image-3.2.0-58-virtual:amd64 (3.2.0-58.88), linux-image-3.2.0-58-generic:amd64 (3.2.0-58.88), linux-headers-3.2.0-58:amd64 (3.2.0-58.88, automatic), linux-headers-3.2.0-58-virtual:amd64 (3.2.0-58.88, automatic), linux-headers-3.2.0-58-generic:amd64 (3.2.0-58.88, automatic)
Upgrade: iproute:amd64 (20111117-1ubuntu2, 20111117-1ubuntu2.1), unity-2d-common:amd64 (5.14.0-0ubuntu1, 5.14.0-0ubuntu2), linux-virtual:amd64 (3.2.0.57.68, 3.2.0.58.69), unity-common:amd64 (5.20.0-0ubuntu2, 5.20.0-0ubuntu3), linux-generic:amd64 (3.2.0.57.68, 3.2.0.58.69), bc:amd64 (1.06.95-2, 1.06.95-2ubuntu1), dc:amd64 (1.06.95-2, 1.06.95-2ubuntu1), libavahi-glib1:amd64 (0.6.30-5ubuntu2, 0.6.30-5ubuntu2.1), gir1.2-appindicator-0.1:amd64 (0.4.92-0ubuntu1, 0.4.92-0ubuntu1.1), gir1.2-gtk-3.0:amd64 (3.4.2-0ubuntu0.5, 3.4.2-0ubuntu0.6), libappindicator0.1-cil:amd64 (0.4.92-0ubuntu1, 0.4.92-0ubuntu1.1), grub-pc:amd64 (1.99-21ubuntu3.10, 1.99-21ubuntu3.14), avahi-utils:amd64 (0.6.30-5ubuntu2, 0.6.30-5ubuntu2.1), libavahi-common-data:amd64 (0.6.30-5ubuntu2, 0.6.30-5ubuntu2.1), libavahi-common-data:i386 (0.6.30-5ubuntu2, 0.6.30-5ubuntu2.1), gir1.2-appindicator3-0.1:amd64 (0.4.92-0ubuntu1, 0.4.92-0ubuntu1.1), libavahi-core7:amd64 (0.6.30-5ubuntu2, 0.6.30-5ubuntu2.1), libappindicator3-1:amd64 (0.4.92-0ubuntu1, 0.4.92-0ubuntu1.1), libgtk-3-bin:amd64 (3.4.2-0ubuntu0.5, 3.4.2-0ubuntu0.6), linux-headers-virtual:amd64 (3.2.0.57.68, 3.2.0.58.69), libavahi-ui-gtk3-0:amd64 (0.6.30-5ubuntu2, 0.6.30-5ubuntu2.1), linux-image-virtual:amd64 (3.2.0.57.68, 3.2.0.58.69), gdm:amd64 (3.0.4-0ubuntu15.1, 3.0.4-0ubuntu15.2), libavahi-ui0:amd64 (0.6.30-5ubuntu2, 0.6.30-5ubuntu2.1), libgtk-3-0:amd64 (3.4.2-0ubuntu0.5, 3.4.2-0ubuntu0.6), libunity-core-5.0-5:amd64 (5.20.0-0ubuntu2, 5.20.0-0ubuntu3), linux-headers-generic:amd64 (3.2.0.57.68, 3.2.0.58.69), libgail-3-0:amd64 (3.4.2-0ubuntu0.5, 3.4.2-0ubuntu0.6), linux-image-generic:amd64 (3.2.0.57.68, 3.2.0.58.69), python-appindicator:amd64 (0.4.92-0ubuntu1, 0.4.92-0ubuntu1.1), unity-services:amd64 (5.20.0-0ubuntu2, 5.20.0-0ubuntu3), grub-pc-bin:amd64 (1.99-21ubuntu3.10, 1.99-21ubuntu3.14), libappindicator1:amd64 (0.4.92-0ubuntu1, 0.4.92-0ubuntu1.1), avahi-daemon:amd64 (0.6.30-5ubuntu2, 0.6.30-5ubuntu2.1), libavahi-client3:amd64 (0.6.30-5ubuntu2, 0.6.30-5ubuntu2.1), libavahi-client3:i386 (0.6.30-5ubuntu2, 0.6.30-5ubuntu2.1), grub-common:amd64 (1.99-21ubuntu3.10, 1.99-21ubuntu3.14), grub2-common:amd64 (1.99-21ubuntu3.10, 1.99-21ubuntu3.14), libavahi-gobject0:amd64 (0.6.30-5ubuntu2, 0.6.30-5ubuntu2.1), avahi-autoipd:amd64 (0.6.30-5ubuntu2, 0.6.30-5ubuntu2.1), libavahi-common3:amd64 (0.6.30-5ubuntu2, 0.6.30-5ubuntu2.1), libavahi-common3:i386 (0.6.30-5ubuntu2, 0.6.30-5ubuntu2.1), libgtk-3-common:amd64 (3.4.2-0ubuntu0.5, 3.4.2-0ubuntu0.6)
Remove: ubuntu-desktop:amd64 (1.267.1), unity:amd64 (5.20.0-0ubuntu2), unity-2d:amd64 (5.14.0-0ubuntu1), unity-2d-spread:amd64 (5.14.0-0ubuntu1), unity-2d-panel:amd64 (5.14.0-0ubuntu1), unity-2d-shell:amd64 (5.14.0-0ubuntu1)
End-Date: 2014-01-08 10:30:14
root@ltsp:/var/log/apt# apt-get install unity-2d
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:
unity-2d : Depends: unity-2d-panel but it is not going to be installed
Depends: unity-2d-spread but it is not going to be installed
Depends: unity-2d-shell but it is not going to be installed
E: Unable to correct problems, you have held broken packages.
root@ltsp:/var/log/apt# apt-get install unity-2d-panel
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:
unity-2d-panel : Depends: libunity-2d-private0 (= 5.12.0-0ubuntu1.1) but 5.14.0-0ubuntu1 is to be installed
Depends: unity-2d-common (= 5.12.0-0ubuntu1.1) but 5.14.0-0ubuntu2 is to be installed
E: Unable to correct problems, you have held broken packages.
This is a lie:
root@ltsp:/var/log/apt# dpkg -l unity-2d-panel
Desired=Unknown/Install/Remove/Purge/Hold
| Status=Not/Inst/Conf-files/Unpacked/halF-conf/Half-inst/trig-aWait/Trig-pend
|/ Err?=(none)/Reinst-required (Status,Err: uppercase=bad)
||/ Name Version Description
+++-=========================-=========================-==================================================================
rc unity-2d-panel 5.14.0-0ubuntu1 Unity 2D Panel
I had to entirely purge unity-2d-panel and unity-2d-common, and then apt-get install unity-2d worked.
BTW, I found this by inspecting /var/log/syslog. Just in case someone googles the error message:
Jan 8 10:55:29 ltsp gnome-session[
Jan 8 10:55:29 ltsp gnome-session[
Jan 8 10:55:29 ltsp gnome-session[
Jan 8 10:55:30 ltsp gnome-session[
Jan 8 10:55:30 ltsp gnome-session[
Jan 8 10:55:30 ltsp gnome-session[