All of a sudden the folder column disappeared. I'm using the Elastic skin. Never made any changes to anything. Looked at all the settings and didn't find anything where I could view it or not.
may be the same as https://www.roundcubeforum.net/index.php/topic,30077.msg76247.html#msg76247 check the width of your browser window
That was it. I had changed my display settings earlier. When I changed them back it solved the problem.
Thanks!