diff --git a/src/calibre/gui2/preferences/server.py b/src/calibre/gui2/preferences/server.py
index fb0c647029..6564eaae9e 100644
--- a/src/calibre/gui2/preferences/server.py
+++ b/src/calibre/gui2/preferences/server.py
@@ -303,6 +303,7 @@ class NewUser(QDialog):
         self.bb = bb = QDialogButtonBox(QDialogButtonBox.Ok | QDialogButtonBox.Cancel)
         l.addRow(bb)
         bb.accepted.connect(self.accept), bb.rejected.connect(self.reject)
+        (self.uw if not username else self.p1).setFocus(Qt.OtherFocusReason)
 
     def show_password(self):
         for p in self.p1, self.p2:
@@ -317,7 +318,7 @@ class NewUser(QDialog):
         return self.p1.text()
 
     def accept(self):
-        if self.uw.isEditable():
+        if not self.uw.isReadOnly():
             un = self.username
             if not un:
                 return error_dialog(self, _('Empty username'), _('You must enter a username'), show=True)
diff --git a/src/calibre/srv/users.py b/src/calibre/srv/users.py
index 8ea5a5334f..04ba9e7ff4 100644
--- a/src/calibre/srv/users.py
+++ b/src/calibre/srv/users.py
@@ -168,14 +168,18 @@ class UserManager(object):
     def user_data(self, users):
         with self.lock, self.conn:
             c = self.conn.cursor()
+            remove = self.all_user_names - set(users)
+            if remove:
+                c.executemany('DELETE FROM users WHERE name=?', (remove,))
             for name, data in users.iteritems():
                 res = serialize_restriction(data['restriction'])
                 r = 'y' if data['readonly'] else 'n'
-                c.execute('UPDATE users SET (pw, restriction, readonly) VALUES (?,?,?) WHERE name=?',
-                        data['pw'], res, r, name)
+                c.execute('UPDATE users SET pw=?, restriction=?, readonly=? WHERE name=?',
+                        (data['pw'], res, r, name))
                 if self.conn.changes() > 0:
                     continue
-                c.execute('INSERT INTO USERS (name, pw, restriction, readonly)', name, data['pw'], res, r)
+                c.execute('INSERT INTO USERS (name, pw, restriction, readonly) VALUES (?, ?, ?, ?)',
+                          (name, data['pw'], res, r))
             self.refresh()
 
     def refresh(self):