Guake is a dropdown terminal made for the GNOME desktop environment. Guake's style of window is based on an FPS game, and one of its goals is to be easy to reach. Recently, my new Ubuntu 18.04 LTS is meeting a bug. When I was trying to exit a shell, the Guake would hang over there, which makes this application even unable to use.
Finally, I found a solution that works for my system.
sudo apt install --reinstall libutempter0
Hoping it helps.
Dear dudes, I really delight to hear this small note viewed by you and may make a few tiny help. However, it is 2021, and I still could get your response. I do respect the bug, which is a REAL TOUGH GUY!