Starbucks hit by major computer failure

The problem was caused by a failure during a daily system refresh, the company said in a statement. It didn't offer additional technical details.

"We are aware of the point of sale register outage at company-operated Starbucks stores in the U.S. and Canada," the company said. "We are actively working to resolve the outage and our stores will remain open and continue to serve our customers."

The outage also affects Starbucks' Evolution Fresh and Teavana stores.

Stores in Boston, New York, San Diego, Vancouver and other cities were affected, judging from hundreds of customer and employee posts on Twitter. Some stores gave away drinks, only accepted cash, or have closed, according to the messages.

In San Francisco, an employee at one store said they were offering free drinks, though he did not offer many other details. He said he was not sure when service would be restored.

The company operates one of the biggest retail networks in the United States and has expanded to many countries around the world. It counts more than 22,000 stores worldwide and serves millions of customers each day.

On Thursday, Starbucks posted total revenue of $4.56 billion for the fiscal second quarter, up 18 percent from the same period last year. It netted 210 new stores during the quarter.

Not every single store was affected by the computer failure. In Phoenix, Arizona, a worker at one store said their systems were fine, although their credit and gift card readers went down last weekend, he said.

Zach Miners covers social networking, search and general technology news for IDG News Service. Follow Zach on Twitter at @zachminers. Zach's e-mail address is zach_miners@idg.com