I am running Ubuntu 16.04.1 and can confirm the appearance of this error message in the terminal when nautilus is launched. The error sometimes also pops up in a notification window, as observed in Comment #21.
Since I do not use the nautilus-share extension, I simply removed the corresponding package to get rid of this error - as suggested in a comment on the duplicate bug report (https://bugs.launchpad.net/ubuntu/+source/nautilus-share/+bug/225859/comments/3). -- You received this bug notification because you are a member of Desktop Packages, which is subscribed to nautilus-share in Ubuntu. https://bugs.launchpad.net/bugs/211966 Title: nautilus-share report a warning about missing /var/lib/samba/usershares Status in Apache2 Web Server: Invalid Status in nautilus-share package in Ubuntu: Fix Released Status in samba package in Ubuntu: Won't Fix Bug description: Binary package hint: nautilus-share if you start nautilus from console you can see this error message: Nautilus-Share-Message: Called "net usershare info" but it failed: 'net usershare' returned error 255: net usershare: cannot open usershare directory /var/lib/samba/usershares. Error Aucun fichier ou dossier de ce type Please ask your system administrator to enable user sharing. I assume it needs to create /var/lib/samba/usershares in the package To manage notifications about this bug go to: https://bugs.launchpad.net/apache2/+bug/211966/+subscriptions -- Mailing list: https://launchpad.net/~desktop-packages Post to : desktop-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~desktop-packages More help : https://help.launchpad.net/ListHelp