Microsoft's main websites, including Hotmail and MSN, were knocked out of action for most of Wednesday, but the company said it was due to a technical problem rather than a cyber attack.
Users began reporting problems yesterday evening, US time, and by this morning UK time, Microsoft UK issued a statement confirming the problem and that engineers were working on a fix.
A US spokeswoman said a technical problem rendered its domain name servers inaccessible by other web servers. She said the company was continuing to fix the error, although users were able to access some sites at around 6.20pm BST.
Microsoft's main properties, including Microsoft.com, MSN.com and Hotmail.com were affected.
This morning a UK spokeswoman said: "They are aware of the problem and technicians are currently working to fix it."
In a statement on Microsoft's UK site, which was unaffected, Microsoft said: "Microsoft is currently experiencing issues with its websites: Microsoft.com, MSN.com, MSNBC.com, WindowsMedia.com, Encarta.com and Carpoint.com. Users may experience delays in being able to connect to these sites.
"Microsoft.co.uk and MSN.co.uk are currently unaffected by this problem.
"Microsoft is working to resolve these issues speedily and you should try again later. Microsoft apologises for any inconvenience this may have caused.
The outage came a day after Microsoft's New Zealand website was knocked out for more than 24 hours by hackers.
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