diff --git a/src/users.js b/src/users.js
index 70101738b..593e08481 100644
--- a/src/users.js
+++ b/src/users.js
@@ -423,6 +423,8 @@ function update(user, data, auditSource, callback) {
     assert(auditSource && typeof auditSource === 'object');
     assert.strictEqual(typeof callback, 'function');
 
+    if (settings.isDemo() && user.username === constants.DEMO_USERNAME) return callback(new BoxError(BoxError.BAD_FIELD, 'Not allowed in demo mode'));
+
     var error;
     data = _.pick(data, 'email', 'fallbackEmail', 'displayName', 'username', 'active', 'role');