After Nemo file manager installation, set Nemo as default File-Manager and allow desktop handling by Nemo open Terminal (Press Ctrl+Alt+T) and copy the following commands in the Terminal:
xdg-mime default nemo.desktop inode/directory application/x-gnome-saved-search gsettings set org.gnome.desktop.background show-desktop-icons false gsettings set org.nemo.desktop show-desktop-icons true Now enter this command in terminal to check that now Nemo is your default file manager :
xdg-mime query default inode/directory If you want to go back with Nautilus as default File Manager try these commands: xdg-mime default nautilus*.desktop inode/directory application/x-gnome-saved-search gsettings set org.nemo.desktop show-desktop-icons false gsettings set org.gnome.desktop.background show-desktop-icons true
Source : http://askubuntu.com/questions/481742/how-to-replace-nautilius-with-nemo-in-gnome-3