I've lately run into this. Occasionally some apps fail to launch from Dock. I click on the icon and I get an alert beep and nothing launches. This happens right after I've quit that app and then shortly thereafter try to relaunch. If I delete the icon from the Dock, launch it from the Apps folder and then Keep it in the Dock, it's fine again when I use it later. All other bahavior on the machine is normal and I've been doing the usual maintenance routines with Mac Janitor and Disk Utility (Repairing Permissions). All updates are current. Thoughts?