Thanks for sharing the image in your response.
There is one other option to remove the "Other User" and that is through the Terminal app.
Open the Terminal app and at the prompt input the following command and then press enter-
sudo defaults write /Library/Preferences/com.apple.loginwindow SHOWOTHERUSERS_MANAGED -bool FALSE
Reboot the computer and see whether that solves it.
If you ever want to revert back to "Other User" enabled (For whatever reason) then below is the command to be entered in the Terminal App.
sudo defaults write /Library/Preferences/com.apple.loginwindow SHOWOTHERUSERS_MANAGED -bool TRUE
Axel F.