Sorry this is inevitably a bit long as it is complex.
In 11.10 I am accustomed to run Gnome Classic with Unity 2D Launcher as well, giving me the best of both worlds, but it seems impossible to set 12.04 up in the same way.
For four days after an Update Manager upgrade from 11.10 - which went well except for Theme 'White on White' text colour problems and a repeated " could not write bytes: broken pipe" message - the situation was as follows:
when logged in as Gnome Classic there were no traditional Menus, but the 3D Launcher Icons were there in the left-hand panel. But see Edit note below.
There was also a Gnome 2 type bottom panel, but that seemed to be the only visible difference from logging in as Ubuntu.
Gome fallback session is installed and running, and there is no Unity Plug-in shown in System Settings.
[In fact I did have Menus, because I have the ClassicMenuIndicator installed, but quite a few of the options do nothing eg Appearance and Unity2D Launcher.]
However, the menus were there as expected when logged-in as 'Classic no effects', but running 'Unity 2D Launcher' returns an Error Widget saying "could not launch 'Unity 2D Launcher' Failed to execute child process "unity-2D-launcher": (No such file or directory.)"
This despite logging in to both Ubuntu & Ubuntu 2D working as I would have expected.shows both ''unity-2d-shell and 'unity-2d-panel' to be running, andCode:ps ax | grep unityI had periodic uninformative "Sorry, 12.04 has encountered an internal problem" messages, but clicking 'Details' only gave path, and performance did not seem to be affected.Code:apt-get install unity-2d-launcher # returns: ....unity-2d-launcher is already the latest version....
But, suddenly, whilst preparing this Post and frequently switching back and forth between the display choices at login, every thing changed. First I got a series of system failure messages every few minutes,though again the system continued to run OK." System Program Problem Detected:"
Then I found that the Launchers no longer showed in Classic but the Menus had appeared for the first time. Though Ubuntu 2D was still as expected - (there was a monitor Icon top right in the toolbar in place of a gear or my username, which I had not previously noticed) - but logging into Ubuntu gave only Unity 2D.
I cold booted several times, ran 'apt-get unity --reset', which gave a lot of errors and quit,
so I ranCode:unity --reset (process:5084): GConf-WARNING **: Client failed to connect to the D-BUS daemon: //bin/dbus-launch terminated abnormally with the following error: No protocol specified No protocol specified Autolaunch error: X11 initialization failed. Traceback (most recent call last): File "/usr/bin/unity", line 222, in <module> reset_unity_compiz_profile () File "/usr/bin/unity", line 84, in reset_unity_compiz_profile except (GError, AttributeError), e: NameError: global name 'GError' is not definedand rebooted, then reinstalled unity.Code:sudo apt-get remove --purge unity
So far - two hours worth - I have had no more system program problems -- Woops -- after re -running 'unity --reset', which gave the same errors as before, I got another system message.
Can anyone suggest what might be the cause and cure for this mix-up.?
Especially, what do you get when logged into Gnome Classic?? Menus and/or Launchers??
Edit: The Unity Plug-in has gone from System Settings when logged in to Ubuntu 3D as well.
Edit2: The Classic Menus were there all the time, but were covered by the Global menu and hence were both - almost - invisible and not responsive to mouse Clicks. In Classic No Effects I had added several Launcher Icons to the top Panel, hence their dimmed out images were now visible in Classic also, but not useable.