Nautilus-Share-Message: Called "net usershare info" but it failed

Nautilus uses the net usershare info command to get information about non-root user defined Samba shares. See the net manpage for more about this command.

If that command fails Nautilus assumes there are no such shares and displays the error message it got just in case you want it.

Creating the folder /var/lib/samba/usershares/ should prevent the message from appearing:

sudo mkdir -p /var/lib/samba/usershares/

I've done these two things to correct this:

sudo mkdir -p /var/lib/samba/usershares/

and

sudo chmod go+rwx /var/lib/samba/usershares/

Another easier solution - Add your user into the group sambashare:

sudo usermod -aG sambashare $USER