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In its third major computer outage since June of last year, United Airlines has once again left passengers waiting at its gates at major airports around the country. United Continental Holdings Inc. (NYSE: UAL) owns and operates both United and Continental Airlines. No issues have been reported for Continental flights.

The airlines used Twitter to announce that they are working to resolve the problem, but the company has had nothing further to say about the outage.

In August, a computer snafu caused delays of up to 2.5 hours for some passengers. In June 2011, a problem with its computers lasted 5 hours and disrupted the travel plans of thousands of customers.

Reports are sketchy, but passenger delays have been reported in Chicago and Houston.

Shortly after 11:00 a.m. ET, Reuters reported that the issues have been resolved and operations are resuming for flights affected by the outage.

United Continental stock is trading at $19.81, down about 0.9% in a 52-week range of $15.51 to $25.84.