Create a couple of users on your site Make sure dev debugging is on to see any warnings Log in as a user that has never sent or received any messages Navigate to the message ui (user menu > messages) Confirm: You don't get any errors / warnings Navigate to the profile of a user that you have not sent/received any messages to/from Click the "Message" button on that user's profile page Confirm: You are taken to the messaging page Confirm: A new message is started with the user and you can send a message to that user Confirm: You do not see any of the warnings mentioned in the description of this issue Send that user a message Log in as the user you just sent a message to Open the messages popover in the nav bar and click on the message you just received Confirm: You are taken to the messaging page Confirm: The message you clicked is loaded up Confirm: You did not get any errors / notices on the page