unable to upgrade ubuntu from 14.04 to 16.04

[Colin Law]

On 26 March 2016 at 08:27, 李白|字一日 <calidion at gmail.com> wrote:
> hi, all
>
> I have tried many times to upgrade ubuntu from 14.04 to 16.04, but failed.
> with command:
> sudo update-manager -d
>
> it seems it is due to the gnome/gtk problems:
>
>
> debconf: 无法初始化前端界面：Gnome
> debconf: (Can't locate Gtk2.pm in @INC (you may need to install the Gtk2
> module) (@INC contains: /etc/perl /usr/local/lib/perl/5.18.2
> /usr/local/share/perl/5.18.2 /usr/lib/perl5 /usr/share/perl5
> /usr/lib/perl/5.18 /usr/share/perl/5.18 /usr/local/lib/site_perl .) at
> /usr/share/perl5/Debconf/FrontEnd/Gnome.pm line 91.)

First check that
sudo apt-get update && sudo apt-get dist-upgrade
shows no errors, then try

sudo do-release-upgrade -d

Colin