A week ago I was updating my Karmic Koala, when suddenly the electricity went off. It was in the middle of installing updates. I use laptop but when wall socket is available I remove the battery, usually I use uninterruptible power supply (UPS),  but unfortunately not that day.
When electricity was back, I started the laptop, it booted just fine, but whenever I try to install I got this error :

subprocess installed post-installation script returned error exit status 2

Thanks to this super awesome article at Khattam.info, my Karmic Koala was back and climbing in no time :)
S/he offers 3 methods that's must be done step by step, but I found that the last step gets the job done and that is editing and removing description of problematic packages within /var/lib/dpkg/status. After that I reinstalled those once problematic packages.

Electric company in my country is well-known for sudden and frequent shut down, so UPS is a must.
Note to myself : UPS is your PC best friend.

best friend

keyword :  ubuntu | update error | error exit status 2