When installing software in Ubuntu Linux operating system using apt-get command, failures may occur due to messages that could not be validated in the console. To tackle the issue, the installation process or the update process can be closed without killing it. To unblock the apt-get, the console mode of operation has to be chosen and the message validated in the console. In case there are failures with the apt-get, or it is not possible to unblock the apt-get, the process has to be killed or forcefully preempted. The killall command executed from the console with -9 argument will preempt the process. An updated version of the apt-get must be installed before proceeding further.
If you ever encounter a failure with apt-get, perform the operations on a console under root:
Kill the process named apt-get: killall -9 apt-get
Reconfigure dpkg: dpkg --configure -a
Update apt-get: apt-get update
Update packages, including improperly installed: apt-get upgrade
Unblocking the message to be validated
It may be that the failure occurred, because a message that was to be validated in the console. Simply close the installation process/update without really finishing or killing it.
You are still able as root and console, to:
Show the details to get the console mode if you are using graphical mode.
Select the message to validate, you move with the <Tab> key then press the<Space> key to validate.