Why is the number of unread messages in Messages negative? Occasionally, and with no apparent correlation with what is going on on other devices where I have Messages enabled, I get a negative count for my unread messages in Messages on OS X:



What could be causing this, and how can I prevent from happening in the future?
I believe that negative numbers show up when you read a message on another device before you read it on what ever device has the negative number. I had the same thing happen to me. I have a "-1" badge on my Messages icon.