Thank you. You are correct and your suggestion works.
This is the first time I have ever seen the "other" user in the login screen. I have four Macs on my Network and one NAS.
The command "sudo defaults delete /L*/P*/com.apple.loginwindow.* SHOWOTHERUSERS_MANAGED" just returns a page of syntax suggestions and arguments and accomplishes nothing.
Copied and pasted
sudo defaults write /Library/Preferences/com.apple.loginwindow SHOWOTHERUSERS_MANAGED -bool FALSE
and it worked. Now it's gone. Thank you.
And just for the record, there is no "other" user folder, I don't have "Find My Mac" enabled, and I don't have guest account enabled.