Nothing like shutting down all flights at the start of a holiday weekend.
http://www.chicagobreakingnews.com/2009/07/computer-glitch-causes-long-lines-at-ohare.html
http://www.suntimes.com/news/metro/1649504,w-united-airlines-ohare-computer-glitch-070209.article
I dunno how it could have been the "check-in system" when they said that outgoing planes were stacked in the penalty box and arrivals couldn't get gates, but I guess they could have not wanted to let empty jets roll out.
http://www.chicagobreakingnews.com/2009/07/computer-glitch-causes-long-lines-at-ohare.html
http://www.suntimes.com/news/metro/1649504,w-united-airlines-ohare-computer-glitch-070209.article
I dunno how it could have been the "check-in system" when they said that outgoing planes were stacked in the penalty box and arrivals couldn't get gates, but I guess they could have not wanted to let empty jets roll out.