Behind the News: A Surrey IT Expert Discusses This Week’s Microsoft Outage

Published on: 14 Nov, 2026
Updated on: 14 Nov, 2026

This week, Microsoft suffered a massive, 24-hour global outage across its core cloud and productivity services, disrupting millions of users in over 70 countries. Services have now been restored and the company has apologised.

Professor Nishanth Sastry, Associate Head of Research and Innovation at the University of Surrey, has explained to The Guildford Dragon what he believes could have happened.

He said: “I am not sure that this is AI-related. There seems to be some suggestion that this might be due to configuration issues. One of the comments in a Hacker News discussion says ‘our review of recent changes has identified a small number of configuration updates that we’re investigating as potential contributors to the issue’.”

The Professor added: “The symptom is that some servers are failing health checks, which say whether the server is operational or not. This failure then leads traffic to be routed to other servers.

“If sufficient numbers of servers fail health checks at the same time, then the remaining servers get overloaded, sort of like when there is a bug like a cold going around and many employees call in sick, leading to overload on the other employees. This shows up as an availability issue wherein Microsoft services are not able to be accessed.

“It is ironic that this means we are not able to access emails, including old emails from yesterday or years back. Email was designed in a world where we couldn’t and didn’t expect always-on connectivity. Protocols like IMAP and even Classic Outlook clients allow us to access emails on our own machines.

“But more recent updates to Outlook have emphasised live sessions and authentication, which means we are thrown out of our accounts during availability incidents like this. Of course, many simply use the web-based Outlook, which does not leave offline copies at all.

“A simple fix is to use a standards-compliant IMAP client like I do, which means, even if I cannot receive new email, I still have access to my entire past email database even if I am disconnected due to incidents like this.

“Keeping ourselves ready for disconnection should be part of our ‘prepping’ process, which the Government has recently started advocating. This is useful not just when we have configuration issues etc, but also if there is an active attack that takes down global infrastructure.”