Microsoft has blamed an internal problem for leaving millions of Hotmail users unable to access their email on Friday.

The service, along with MSN Messenger, suffered an outage early Friday evening (UK time), although it is now understood that the service is fully up and running again.

A spokesman for MSN told The Register that, along users around the world were hit. He ruled out any notion that the email service was the subject of a malicious attack. He also declined to discuss the nature of the internal problem.

Although he couldn't say how many people were hit by the problem he described it as "extensive", adding that it hit a majority of Hotmail's 140m users, locking them out of their email accounts. ®