CHICAGO (CBS) — Computers at Starbucks in Chicago, and apparently across the country, crashed on Tuesday morning, leaving customers unable to order their morning lattes.

Computers were down at two locations in the Loop, according to witnesses. Workers there were giving away free regular coffee as compensation.

As people learned of the free coffee offer, lines began to form outside downtown stores. According to witness accounts, the systems started to come back online in the Loop around mid-morning.

Customers line up at a Starbucks under Daley Plaza after hearing the company was giving away free coffee after a computer malfunction. (CBS)

At a location underneath Daley Plaza, near the Washington Street Blue Line, workers were giving away food as well and customers cleared out the shelves.

This Starbucks downtown was giving away free coffee drinks and food after a computer malfunction. (CBS)

It was not immediately clear what caused the malfunction or how many stores were affected.

On Twitter, people across the country were reporting similar issues.

According to Starbucks, they were working overnight to install a technology update in U.S. and Canada, saying, “A limited number of stores are offline because of a glitch, so cash only.”

Starbucks said they are working to have the computers back up as soon as possible.