Thousands of Starbucks stores were hit by a computer outage on Friday forcing many stores to give away free drinks, while many closed early to the disappointment of Starbucks lover.

Starbucks later released a statement saying the outage was resolved Friday night after several hours. It affected registers at 7,000 company-operated stores in the U.S. and 1,000 in Canada.

"All Starbucks stores in the U.S. and Canada are expected to open for business as usual on Saturday," the company said in a statement late Friday night. "We apologize to our customers for this inconvenience." Stores on the East Coast with early hours were open Saturday morning.

The problem started in the early evening Friday on the East Coast and in the late afternoon on the West Coast.

The company said the stores that had not already closed for the evening were closed early. Starbucks said the outage was caused by "a failure during a daily system refresh." Company spokesman Jim Olson said that could be called an internal computer system failure but asserted that it was an internal issue and did not involve any external breach.

Some stores were shut down, while some offered free brewed coffee or tea. In Phoenix, some stores blocked off the entrance to their drive-thrus. At Starbucks store in Seattle's South Lake Union neighborhood, customers were told that the staff members couldn't process orders. They were, however, being offered coffee at no charge.

At a company's store in Phoenix, many customers were seen driving away angrily after seeing closed signs.