The incident was still being fixed at the time of writing. Treat this as a live picture, not a final damage report.
What Microsoft has confirmed
The admin-center incident is EX1550543. Microsoft describes it as users being unable to reach their Exchange Online mailboxes through several connection methods: Outlook on the web, MAPI, Exchange ActiveSync and the REST API. The companion Microsoft 365 advisory is MO1550821, which covers impact on other services. Service-health updates republished by Cloud Admin Hub put the start of the Exchange incident at 16:17 GMT on November 12.
Microsoft's updates over the night, in order:
- Affected servers were failing automated health checks and dropping out of service.
- That pushed extra load onto the servers still running, which made things worse.
- A process on those servers that sets up secure connections was getting overwhelmed.
- Microsoft started reverting a recent network configuration change that lined up with the start of the problem.
- Servers it restarted could go unresponsive again once traffic returned.
CBC quoted one Microsoft status update admitting that a planned fix was "not taking as expected."
By Friday, Microsoft reported better server stability after applying a patch to an upstream authentication/routing configuration component on part of its infrastructure. It was expanding that patch to regions entering business hours first. It also extended the email timeout window to 48 hours so delayed mail is less likely to bounce. Microsoft says it is not aware of any malicious activity and will publish the root cause in a Post-Incident Report.
On scope: Yahoo News, citing Downdetector, reported that the outage had been reported in 74 countries and territories within about an hour. That counts complaints, not affected users. The Guardian also called the disruption patchy: some users kept partial access, and some regions recovered sooner than others.
Section summary: The problem was in Microsoft's server infrastructure, not an attack Microsoft has found, and the exact root cause had not been published at the time of writing.
Japan: fax, phone and bulletin boards
The outage reached Japan on Friday morning as people were starting work. The Japan Times reported error screens, rescheduled meetings and work disruption. It quoted one person on X who couldn't open Outlook, panicked, and was told by their boss to stay home.
The fax jokes spread quickly on Japanese social media. Some people said they were faxing updates they would normally send as PDF attachments. Those posts show a mood, not how many people actually switched.
The institutional reports carry more weight:
- Government email: the Guardian's live coverage reported Japan's digital minister saying government email was unavailable and that text messages would be used in the meantime. A shared network the Digital Agency uses to send information to ministries was also hit.
- Business: shipping firm Sagawa Express couldn't accept online reservations for its airport and station luggage service, and drugmaker Taisho took orders by phone.
- Government press briefings: the Cabinet Office used bulletin-board notices for media briefings.
- Not affected: Japan's meteorological agency said it doesn't use Microsoft to send special weather and earthquake warnings to local governments.
A few details come only from Pasquale Pillitteri's account, which cites the Japan Times, and couldn't be independently confirmed here. They include a 2025 Keyman's Net survey finding more than 78% of polled companies use Microsoft products, contact-form delays at credit card issuer Credit Saison, and problems at Kyushu and Waseda universities.
Australia: probably the hardest hit
Timing explains much of Australia's experience. The outage started on Thursday afternoon in the US, which was Friday morning in Australia, just as the working day began. The Guardian reported that councils, state and federal agencies, courts and schools all warned they couldn't be reached by email.
- Western Australia said Microsoft was prioritizing life, safety and government services. It also said classroom teaching continued normally and four paper-based exams were unaffected.
- Victoria reported no significant impact on frontline emergency response, clinical care, public transport or VCE exams at that point, but warned that scammers were exploiting the confusion.
- The Department of Foreign Affairs and Trade sent urgent sanctions enquiries to its sanctions office by phone. The Department of Agriculture, Fisheries and Forestry warned clients that email to and from its systems might fail.
- The Australian Medical Association reported clerical problems at some hospitals and clinics but no patient-care impact among the facilities it had heard from.
- AP reported that ASIO, Australia's intelligence agency, and Singapore's Government Technology Agency were affected. Neither gave operational details, and nothing reported suggests any sensitive operation was compromised.
On the cause, Yahoo News quoted Home Affairs Minister Tony Burke saying that "The perspective of Microsoft at this stage, they do not believe they are dealing with a cyber event." Pillitteri's account goes further and says Burke described a botched update. That remains the minister's interpretation, not something Microsoft has confirmed.
United Kingdom: email failed, clinical systems mostly didn't
The NHS response shows the pattern seen in many places: communications broke, but care continued.
- NHS Essex said some NHS email and Teams systems were affected. Patients were told to keep scheduled appointments unless contacted, use NHS 111 for urgent help and call 999 for life-threatening emergencies. It set up a temporary phone line for health and care providers making referrals, not for the public.
- Queen Elizabeth Hospital King's Lynn said its clinical and patient-administration systems were working, with no impact on patient care, though staff emails could be delayed.
- National Rail warned that emailed train tickets might be inaccessible. Its advice was to try the retailer's website or app first. If you bought as a guest, contact the retailer. If that fails, ask station or onboard staff.
The Guardian also reported that Ofsted couldn't receive email and that the Bank of England said its critical operations were running normally. The Financial Conduct Authority was monitoring the effect on City firms, since Microsoft is among the critical suppliers it oversees.
Germany, New Zealand and Canada
Germany: Pillitteri reports that Deutsche Bahn had severe email delays that made it hard to send out schedules for diverted trains. That specific claim couldn't be independently confirmed here, and nothing suggests trains themselves stopped running. The Guardian separately reported that government agencies in Germany, the Netherlands, Belgium and France had problems.
New Zealand: this is one of the better-documented cases. Immigration New Zealand's official notice says it paused processing of all visa applications until further notice, and customers couldn't apply through its enhanced Immigration Online platform. NZeTA requests continued as normal. The agency also pushed back system changes planned for Monday, November 16 by a week, to November 23.
Canada: Unity Health Toronto's own notice says it declared a Code Grey in response to a worldwide Microsoft 365 service outage after staff had trouble sending and receiving email. It told patients to call them via the main hospital line (if urgent) or wait until email services are restored. It told staff to use other channels or the internal UnityNet site, and said patient and resident care is not affected by the outage. CP24 explained that Code Grey is called when there is a loss or failure of infrastructure. CP24 also reported email problems at the University of Toronto, Seneca Polytechnic and George Brown Polytechnic.
Financial markets: hit even without an Outlook inbox
Reuters, republished by AOL, reported that Euronext asked listed companies on Friday morning to phone in corporate information. Euronext runs markets in Amsterdam, Athens, Brussels, Dublin, Lisbon, Milan, Oslo and Paris. Pillitteri, citing Reuters via the Guardian, adds that Euronext's corporate actions and listings offices weren't receiving email. The phone instruction is corroborated; the office-level detail is not.
The Guardian also reported that some portfolio managers couldn't use email to authenticate to certain trading platforms. When email doubles as a login factor, an email outage locks people out of other systems too.
What admins should take from this
The common thread is clear. Clinical systems, classrooms, emergency services and trains largely kept running. What failed was the communication layer: referrals, enquiries, tickets, visa intake and corporate filings. The organizations that coped best already had another channel ready to publish.
Practical steps, based on what worked in the notices above:
- Track the right incidents. In the Microsoft 365 admin center, go to Health > Service health and follow EX1550543 and MO1550821.
- Publish an alternative contact channel before you need it. NHS Essex's provider-only phone line and Unity Health's main-line instruction are good models. Say who each channel is for.
- Don't assume your email arrived. Tell partners to confirm urgent messages by phone. Microsoft's 48-hour timeout extension helps queued mail survive, but a queue isn't delivery.
- Expect scams. Victoria's warning applies everywhere. Fake "Microsoft restoration" emails and calls tend to follow outages like this.
- Find where email is a login factor. If email-based authentication protects other systems, those systems need a fallback too.
- Look at your contract. Customers with financially backed uptime commitments should check their Microsoft agreements for service credit eligibility. Exact terms and deadlines depend on the agreement.
One caution: a second email provider isn't a magic switch. RMIT's Mark Gregory told the Guardian that organizations should have backups such as Gmail. That only helps if the alternative is set up, tested and known to staff before the outage. Is a backup channel you've never tested really a plan?
Bottom line: No country-by-country list of impact is official yet, Microsoft hasn't published a root cause, and a definitive ranking of the hardest-hit countries would be premature. What is already clear is that the places that kept working had a phone line, a paper process or an internal site ready before Exchange went down.