DesktopServer – Create locally installed WordPress Websites › Forums › Public Discussions › 'Unable to connect' message after upgrade to osX 10.10.4 › Reply To: 'Unable to connect' message after upgrade to osX 10.10.4
It sounds as though your services are not running. Can you go into your activity monitor and be sure that httpd and mySql are running?
Also, have you tried a clean reboot?
When you start DesktopServer and click on the “Sites” Button, what do you see?