Many Starbucks customers found themselves with caffeine withdrawal symptoms early Tuesday, as some store locations in the US and Canada experienced a payment system outage. The company has said a software update caused the outages.
Cash registers were pushed offline during the update, according to Starbucks spokeswoman Madeleine Löwenborg-Frick.
"Our systems have not been compromised by any third party," she told Reuters, adding the affected stores should be back online "shortly."
Löwenborg-Frick would not indicate how many stores were impacted by the outage.
The software update was done in routine fashion, the company said in a statement.
"As part of our normal course of business, overnight we worked to install a technology update to our store registers in the U.S. and Canada," the company said, according to CNBC.
"The stores will remain open during this time and, as always, our partners are prepared to take care of our customers to ensure they have the best experience possible," the company added.
Some stores that remained open during the outage required customers to pay cash only for their morning coffee. Others offered customers a free beverage for the inconvenience, according to reports.
Some on social media assumed the outage was related to the weekend's worldwide ransomware attack, known as WannaCry, that infected hundreds of thousands of computers in 150 countries.