What is causing the Microsoft outage? Key problem at centre of tech collapse identified by expert

The Microsoft outage which has hit millions of people around the world was caused by “overloaded servers,” say tech experts.

Bob O'Donnell, founder of TECHnalysis Research, explained that this would have led to "overloaded servers".

He told the BBC: "A Microsoft exec posted on social media...’It is not cyber. It's not malicious’. It's simply they've overloaded these servers.

"Now, it's not a good sign. I mean, let's be honest. The numbers are going to be millions.”

Other experts outlined possible additional and more detailed reasons for the outage.

Alan Woodward, Professor of Cybersecurity at Surrey University, said: “It’s chaos.

“If I were a betting man I reckon it’ll be a cascade failure to do with the health check, some configuration change internally that triggered it, and progressive inability of other servers to cope with the extra load i.e. a cascading failure.”

Awais Rashid, Professor of Cyber Security at Bristol University, added: “What is concerning is not only that an overload issue occurred but, more critically, that Microsoft does not seem to fully understand the underlying cause and apply an effective fix.

“Cloud systems are large and complex. However, capability to ensure their effective operation and mitigation of issues such as this is critical.”

Microsoft is scrambling to find new ways to restore services after a global outage has left hundreds of thousands of users worldwide without access to emails and Teams as it admitted fixes were not going ‘as expected’

PA Archive

Monitoring website Downdetector first showed a spike in users reporting problems with Microsoft Teams in the UK at around 6.15pm on Thursday.

Issues were still being reported at 3am the following morning.

Microsoft executive vice-president Charles Lamanna said the outages did not appear to be the result of a cyber attack.

“We regret that today’s outages caused disruptions for our customers, and we are working to address the issue,” he wrote on X.

“We will continue to share more information as soon as we have it, and for now I can confirm that there is no indication this is the result of malicious or cyber activity.”

Affected products included instant messaging service Teams, AI service Copilot, Outlook emails and some aspects of its Cloud services, among others.

An error message is shown when trying to access Outlook

Getty

In an update on Friday, the tech giant said that although it had managed to get servers operating multiple times overnight UK time, those servers had crashed.

OpenAI, the company behind ChatGPT, also reported issues.

Microsoft said it had tried several solutions to mitigate the problems, including isolating parts of its infrastructure and shifting traffic to alternate routes.

“We’ve monitored the status of the changes applied to improve serviceability and confirmed that change is not taking as expected,” the company said.

Microsoft has been hit with outages (Niall Carson/PA)

PA Archive

In Britain, Whitehall computer experts were assessing how badly the Government was affected by the outage.

"We're looking across Government at the moment as to the impact of Microsoft services as one of the key providers, not just for Government services but industry services. We recognise that the outage has potential to cause a lot of trouble," Defence Minister Luke Pollard told Times Radio.

“There's an awful lot of frustrated people this morning trying to get into their systems, trying to access their emails and other services that Microsoft provide. I want to see this fixed.”

Multiple governments around the world also reported Microsoft outages, including in Australia, India and Japan.