Fcitx occasionally occupies 100% CPU on Ubuntu when you use sogou-pinyin. To fix it without restarting the computer:

  1. Restart fcitx

     $ fcitx -r

  2. Disable ibus-daemon

    You will need to disable ibus-daemon if the above command fails to execute and shows something like “Start XIM error. Another XIM daemon named ibus is running?” If you simply kill the process, it will respawn soon. Find the executable and rename it.

     $ sudo mv /usr/bin/ibus-daemon /usr/bin/ibus-daemon.bak

  3. Uninstall apport

    After restarting fcitx, apport might complain. It is fair enough to get rid of the annoying apport pop-ups by just uninstalling it, since Canonical is never in short of bug tickets.

     $ sudo apt-get purge apport