If you install a fresh manjaro i3 OS on your system and try to do Mod+d, you might face a problem related to the dmenu. Manjaro has its dmenu already installed so you can’t get any other dmenu but this one won’t work. The reason is due to missing or incorrect locale giving error like below. Probably you have selected Indian locale language.
warning: no locale support
What you need to do in this case is first setup the locale with command below:
sudo localectl set-locale LANG=en_IN.UTF-8
Then you have to go to edit /usr/bin/dmenu_run in sudo mode and right after the shebang line, add the following
LANG=“en_IN.UTF-8”
Once this is added, restart your system and the manjaro dmenu should popup with Mod+d in top of your screen.