はじめまして。
最近Ubuntu16.04にCUDA8をインストールしたのですが、ログインループにはまってしまいました。.xsession-errorsには以下の事が書かれています。

operConnection:connect:No such file or directory
cannot connect to brltty at :0
upstart:gnome-session(Unity) main process(3080)terminated with status 1
upstart:unity-setting-daemon main process(3060)terminated with TERM signal
upstart:logrotate(2887)killed by TERM signal
upstart:hub main process(3058)killed by TERM signal
upstart:unity-panel-service main process(3086)terminated with TERM signal
upstart:bamfdaemon main process(2984)terminated with TERM signal
upstart:Disconnected from notified D-Bus bus