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I am suffering from the bug which crashes Ubuntu when I click Alt+Tab: .

While I was doing a do-release-upgrade -d just now to install 12.04, I accidentally clicked Alt+Tab. Now Unity crashed, Alt+Ctrl+F2 doesn't work. All I have is a blank screen. Usually Unity used to restart by itself but it didn't this time.

So my question is, since the upgrade has already finished downloading the packages and was installing them during the crash, should I leave the PC alone as it maybe still installing in the background? Or should I restart it (by holding the power button or Ctrl+Alt+Delete)?

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up vote 2 down vote accepted

The exact same thing happened to me. Here is my story:

  1. During upgrade Unity crashed and I basically had access to nothing; Couldn't even open a terminal with Ctrl+Alt+T. The hard disk was still working, so I figured the update was still running, and I left it.
  2. Eventually the disk activity stopped, so I had to assume the update was complete and forced a log out with Alt+SysReq+K, then a restart.
  3. Upon loading Ubuntu again, I noticed I was getting an incorrect screen resolution so I knew something was up. I managed to log in, then ran Updates and was given an error about the upgrade being interrupted.
  4. I had to open a terminal, first tried: sudo apt-get install -f, but this told me that I needed to run sudo dpkg --configure -a
  5. This seemed to resume the upgrade process where it had left off, so I left it for another while. I got a few console prompts about replacing my desktop defaults file, so I guess when I had restarted previously it was waiting for some such reply (but I had no way of seeing it).
  6. After this completed, seemingly with no errors, I ran sudo apt-get install -f again just to be sure. After that I rebooted and everything seemed dandy. Phew.

Of course if someone else has this problem their results may very, but maybe this will give someone some hope if their Unity crashes during the update (grr).

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In my case, after I restarted Ubuntu was lagging like hell. And choosing the recovery mode in the GRUB was starting Ubuntu normally. Luckily, Ubuntu keeps old Linux kernel available, thus I was able to go to previous Linux releases then choose recovery mode from an older release. And I run sudo dpkg --configure -a – Dan Apr 27 '12 at 7:17
I dare say this saved my ass! My wouldn't boot up again so I had to access a shell with ctrl + alt + f2 and run these commands. – Dunhamzzz Apr 30 '12 at 9:58

Here is what I did and I managed to restart unity and continue upgrade normally

  1. Press Ctrl + Alt + F1 and logged in
  2. killall unity-panel-service
  3. killall compiz
  4. ps ax | grep unity and killed everything with kill -9 pid#
  5. Ctrl + Alt + F7 done
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