(Reuters) - Tens of thousands of customers of banks owned by Britain's Lloyds Banking Group
"We apologize that earlier today, between 3 p.m. and 6 p.m., some customers were unable to complete their debit card transactions," Lloyds said in a statement.
"Although the majority of transactions were unaffected, we are very sorry for the inconvenience that this will have caused."
Approximately half of the company's 7,000 ATMs were affected, Lloyds said, adding that the problem was resolved by 7.30 p.m.
A similar problem hit Royal Bank of Scotland
The Financial Conduct Authority has been scrutinizing the resilience of all banks' technology to address concerns that outdated systems and a lack of investment could cause more crashes.
A software upgrade gone wrong in June 2012 cost RBS 175 million pounds ($286 million) in compensation for customers and extra payments to staff after the bank opened branches for longer in response.
(Reporting by Aashika Jain in Bangalore; Editing by Robin Pomeroy)