The Microsoft 365 outage has run for more than 18 hours. Microsoft opened the incident at 17:54 UTC on 12 November, and its service health post at 12:00 UTC on 13 November still listed the service as degraded across 20 Microsoft 365 services, up from 11 on the first evening. The BBC reported that Downdetector had 140,000 people from 74 countries report issues with Outlook on Thursday evening.
That 12:00 UTC post says “We’re seeing encouraging recovery progress in Europe” and that North America is improving, but warns “some users may still experience intermittent issues as recovery actions continue”. It gives no time for a full fix. Our arithmetic: 17:54 UTC on 12 November to 12:00 UTC on 13 November is 18 hours and 6 minutes.
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The key insight:Microsoft’s 12:00 UTC post on 13 November listed 20 Microsoft 365 services as affected, up from 11 on the first evening, and says features that interact with Exchange Online are impacted. By our arithmetic the outage had run 18 hours and 6 minutes at that post.
Microsoft’s post explains why so many products fail together. It says: “Features of the Microsoft 365 services below that interact with Exchange Online and email services are impacted.” It adds: “Elements of those services that do not depend on interaction with Exchange Online remain functional.”
In other words, the mailbox layer sits under the rest. Microsoft lists Exchange Online first: users may be unable to reach their mailbox through Outlook on the web, Outlook desktop, Exchange ActiveSync or REST connections, and email delivery may be delayed. For Copilot, it says users may be unable to load Copilot Chat or get responses, and “Copilot experiences may be unable to access work data such as email, calendar, and files.”
Microsoft says reducing email queues and backlogs remains a priority, and that an extended 48-hour email timeout window stays in place to protect delayed messages. It also says: “At this time, we have no evidence of malicious activity associated with this incident.” It promises a full Post-Incident Report with root cause after mitigation and set its next update for 13:00 UTC.
Earlier, at 10:28 UTC, Microsoft’s @MSFT365Status account said service health “remains variable and capacity has not yet fully returned to baseline.” The BBC’s live page reported a Microsoft statement saying recovery actions were complete across parts of the Asia Pacific region: “Traffic is being gradually restored, and we’re seeing improvements in key customer scenarios, including mailbox access and delayed email processing.”
Microsoft’s own Microsoft 365 status posts from the first, at 17:54 UTC on 12 November, to the 12:00 UTC update on 13 November. Hours since the first post are our arithmetic.
What Was Posted on X
Recovery actions are ongoing across affected Microsoft 365 infrastructure and progressing in phases. We’re seeing incremental improvement in several workloads, but service health remains variable and capacity has not yet fully returned to baseline. To protect delayed mail, we’ve extended the email timeout window to 48 hours while queue and backlog processing continues. A more comprehensive update can be found at MO1550821 in the Microsoft 365 admin center, as well as https://status.cloud.microsoft/ if the admin center is not available to you.
Microsoft’s official Microsoft 365 Status account posted this at 10:28 UTC on 13 November, more than 16 hours after its first post on the incident. It says recovery is progressing in phases, capacity has not yet fully returned to baseline, and the email timeout window has been extended to 48 hours. This piece uses it for the recovery timeline.
‼️ UPDATE: Microsoft 365 is still broken after more than 14 hours, and Europe is starting work with Outlook inboxes that won’t open.
Microsoft says its servers are steadier since it patched an authentication and routing configuration component. It gives no time for a full fix.
Outlook, SharePoint, OneDrive and Copilot are down or badly hit, and Teams calendars fail. Intune and Defender, which IT teams use to manage and protect staff devices, are hit too.
Downdetector peaked at about 140,000 Outlook reports. The BBC counts at least 74 countries affected, from Australia’s spy agency ASIO to courts in Singapore, Los Angeles and Texas.
Servers Microsoft brought back froze again once traffic hit them. It says this is not a cyberattack.
Early on, it said it had found no recent change linked to the outage. The Guardian reports it now suggests server configuration settings may be to blame.
— International Cyber Digest (@IntCyberDigest) Nov 13 09:44
International Cyber Digest posted this summary at 09:44 UTC on 13 November, relaying a Downdetector peak of about 140,000 Outlook reports and the BBC’s count of at least 74 countries affected. Gennaro Cuofano passed it to the desk; this piece checks those figures against the BBC and Microsoft rather than relying on the post.
MICROSOFT ON OUTAGE SAYS TRAFFIC IS BEING GRADUALLY RESTORED, AND WE’RE SEEING IMPROVEMENTS IN KEY CUSTOMER SCENARIOS
First Squawk relayed Microsoft’s statement at 11:07 UTC on 13 November that traffic was being gradually restored, with improvements in key customer scenarios. The BBC’s live page carried the same Microsoft statement, which this piece quotes.
Some of the additions matter beyond mail. Microsoft says Graph API requests that touch Exchange Online data such as mail, calendar and contacts may time out. Graph is the interface other software uses to read that data. It says admins may be unable to load some admin center pages, and that some Windows 365 users on one encryption setup may be unable to connect to their Cloud PCs. For Teams, it says joining calls, meetings and chats mostly works, while calendar scheduling, invites and meeting edits fail.
Where the AI Connectors Stand
The outage also reaches AI tools from outside Microsoft. Anthropic’s status page opened an incident on the Microsoft 365 connector at 17:52 UTC on 12 November. Its latest update, at 22:23 UTC, said the problem is caused by a Microsoft 365 service incident and that “mail, calendar and search tools in the Microsoft 365 connector are still failing for most requests”. It said Claude for Outlook remained affected. When we read it on 13 November, the incident showed no resolution.
OpenAI’s status page still shows its incident as investigating. It says OpenAI is “investigating an issue with Microsoft connectors where new connections may be broken and tools are not working as expected”. The BBC also reported that OpenAI and Anthropic both reported problems as a result of the outage. A separate Anthropic login incident on 13 November, now resolved, is covered in Claude login errors hit four Anthropic services.
Who Was Hit
The BBC said courts from Los Angeles to Texas warned that communications might be delayed, that a Toronto healthcare network had email issues, and that the government of Japan said its shared IT platform had been disrupted. Reuters reported that Australia’s spy agency ASIO and the federal police were affected; Home Affairs Minister Tony Burke said Microsoft told him it did not believe a cyber attack caused the outage.
In the UK, NHS England said “local NHS services are enacting long-standing measures to manage IT outages”, including using other IT systems or paper records where possible. King’s College Hospital said it cannot send or receive emails, while services for patients are running as usual. The BBC’s live page reported that Richemont delayed its half-year results because of the disruption.
Security researcher Troy Hunt told the BBC: “Microsoft is a massive part of the internet backbone and reminds us how critical email still is.” The BBC noted that Downdetector relies mainly on users self-reporting, so the real number affected is likely much higher; Microsoft says more than 430 million people use Microsoft 365 apps.
The Structural Read
As we read Microsoft’s post, the outage is less a list of 20 broken products than one shared dependency showing through. Microsoft itself says elements that do not depend on Exchange Online remain functional, while Copilot, Graph, Teams calendars and Purview are listed because they reach into mail and calendar data. Anthropic’s status page attributes its own Microsoft 365 connector failures to the same Microsoft incident.
Microsoft service health post, 13 November 2026, 12:00 UTC
“Elements of those services that do not depend on interaction with Exchange Online remain functional.”
Three Implications
FOR IT AND OPERATIONS TEAMS Microsoft says it extended the email timeout window to 48 hours to protect delayed messages, so mail sent during the outage may still arrive as queues clear.
FOR COMPANIES BUILDING AI ON MICROSOFT 365 DATA Microsoft says Graph API requests that access Exchange Online data may time out, and that Copilot may be unable to access email, calendar and files.
FOR USERS OF CLAUDE AND CHATGPT CONNECTORS Anthropic says mail, calendar and search tools in its Microsoft 365 connector were still failing for most requests at its last update, and OpenAI’s Microsoft connector incident still shows as investigating.
The framework says: “The value proposition shifts from features to integration depth.”
As we read it, the second day of this outage shows the other side of integration depth: Microsoft lists Copilot and 19 other services as affected because they reach into the same mail and calendar layer. The framework predates the outage and does not discuss it.
The 20 services Microsoft listed as affected at 12:00 UTC on 13 November. Red marks the nine that were not on its list on the evening of 12 November; the comparison is ours.
What Is Not Established
Microsoft has not given a full root cause. The BBC reported that Microsoft attributed the outage to “elevated load” after a large number of servers became “unexpectedly unavailable”; Microsoft says a Post-Incident Report with root cause will follow mitigation, and it has ruled out malicious activity. It has not said how many tenants or users are affected, and the 74-country figure is a Downdetector count of self-reported Outlook problems, not a Microsoft number. Neither Anthropic nor OpenAI has posted a resolution for its Microsoft connector incident. Microsoft gave no time for full recovery.
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By our count the Microsoft 365 outage passed 18 hours at Microsoft’s 12:00 UTC update, and the list of affected services grew from 11 to 20. Microsoft says features that interact with Exchange Online are impacted, and its list runs from mail and calendars to Copilot and Graph. Anthropic attributes its connector failures to the Microsoft 365 incident, and OpenAI’s Microsoft connector incident is still open. In an update at 12:58 UTC, Microsoft reported broader improvements in North America and sustained improvements across much of Europe, still listed the service as degraded and set its next update for 14:00 UTC.
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A note on sourcing. We read Microsoft’s service health post of 12:00 UTC on 13 November in full, Microsoft’s @MSFT365Status posts, the BBC’s explainer and live page, the Anthropic and OpenAI status feeds and King’s College Hospital’s statement. Reuters’ Australia report came through an earlier read. Gennaro Cuofano passed two X posts on the outage, from International Cyber Digest and First Squawk, to the desk; we checked their claims against the sources above. The 74-country figure is the BBC’s report of Downdetector data. We did not contact Microsoft, Anthropic or OpenAI.
Gennaro Cuofano is a CRO and tech executive who has worked in AI since late 2015, starting with bringing NLP, natural-language generation, voice and chatbot products to the marketing industry. His background is in law and finance: he holds a Master's degree in Law and an International MBA with an emphasis on corporate finance (LUISS Business School and the University of San Diego, 2012), and worked as a financial analyst at a real-estate investment firm in San Diego and as an assistant controller. His work focuses on business model strategy, business engineering and, more broadly, structural analysis: how companies make money, read from their own filings. He created FourWeekMBA and leads research there and at The Business Engineer, his newsletter on AI and business strategy, with over 95,000 subscribers and more than 1,000 published analyses. His writing has also appeared on Entrepreneur (for example, How to Digitize a Family Business in Europe) and HackerNoon. Find him on LinkedIn and Substack. See how we source.
