If you run regular automated WebDriver tests using Firefox then chances are you’ve encountered the problem where Firefox updates itself and your WebDriver bindings don’t support that version which causes all your tests to fail. It’s really annoying, so I suggest you set your Firefox install to never automatically update as below to avoid this happening.
As Alex points out below, you can do this programmatically for a server you don’t actually launch Firefox on, ie. a headless machine.
profile = Selenium::WebDriver::Firefox::Profile.new
# disable autoupdate
profile[‘app.update.auto’] = false
profile[‘app.update.enabled’] = false