Macbook crashed now iMessage not working correctly So my computer crashed due to a power cable issue. Now that that's resolved I was attempting to send messages to known iMessage users (ie people I've sent iMessages to prior to the crash) and now something doesn't accept other users as iMessage recipients. It says I'm sending an iMessage and it failed because the user is not registered for iMessage. 

How do I fix this?
Log out.
Log in.
Check for each existing conversation that the small tab at the top of the main window is not red. If it is, click it &amp; re select their correct number/address.