Starbucks suffered what appears to be a major computer system failure late Friday.
Stores in Boston, New York, San Diego and other cities appeared to be affected, judging from hundreds of customer and employee posts on Twitter. Some stores are giving away drinks, are only accepting cash, or have closed, according to the messages.
In San Francisco, an employee at one store said they were giving away free drinks, though he did not offer many other details. He said he was not sure when service would be restored.
Starbucks did not immediately respond to telephone calls and emails requesting comment.
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.