A widespread Microsoft outage disrupted hospitals, government agencies, courts and businesses across the world on Thursday, November 12, 2026, and continued affecting some services into Friday. Problems with Microsoft 365 prevented thousands of users from accessing email, scheduling meetings and using workplace communication tools, forcing essential organizations to rely on alternative methods.
The disruption affected Microsoft Outlook, Teams, SharePoint and the company's Copilot artificial intelligence service. Hospitals reported problems communicating with patients and staff, while government offices warned residents that email messages might not be delivered.
Microsoft said engineers were restoring affected systems and had made significant progress by Friday. However, some customers continued experiencing intermittent access problems and delayed email delivery as the company worked to stabilize its infrastructure.
Microsoft Outage Spreads Across Multiple Countries
The disruption began Thursday, with reports of problems increasing rapidly around midday in the United States. Users attempting to open Outlook encountered error messages, inaccessible inboxes and problems sending or receiving email.
The outage quickly spread beyond North America, affecting organizations in Europe, Asia and other regions. Downdetector, a website that collects reports of technology problems, received complaints from 74 countries and territories within an hour of the disruption becoming widespread.
Reuters reported that more than 97,000 problems involving Outlook had been reported by 2:07 p.m. Eastern Time on Thursday. The tracking service also recorded more than 38,000 reports involving Microsoft 365 and approximately 4,500 involving Teams.
Those numbers represent submitted outage reports, not confirmed numbers of affected users. A single organization could have hundreds or thousands of employees experiencing problems without each person submitting a report.
The scale of the disruption reflected Microsoft's importance to everyday business operations. Its software provides email, document storage, communication tools and collaboration services to organizations of many sizes.
Problems also affected connections between Microsoft 365 and artificial intelligence services operated by OpenAI and Anthropic. Both companies acknowledged disruptions involving their Microsoft integrations.
Hospitals Struggle With Email and Patient Communications
Healthcare organizations were among those affected, particularly hospitals that depend on Microsoft email systems to coordinate administrative work and communicate with patients.
Main Line Health, a healthcare network in Pennsylvania, warned patients Friday that messages sent through email might be delayed. The organization emphasized that its hospitals and care facilities remained open and that patient care was continuing safely.
Patients were encouraged to telephone their care teams instead of relying on email. The network also advised people to attend scheduled appointments unless they received instructions to do otherwise.
In Delaware, ChristianaCare reported problems extending beyond ordinary email access. Communications involving fax systems and pagers connected to email services were also affected, creating additional complications for staff.
University of Iowa Health Care experienced problems with email and voicemail across its campuses. Patients were directed toward alternative communication methods, including the organization's MyChart patient portal.
These difficulties illustrated how a failure affecting workplace software can interfere with healthcare operations without necessarily shutting down electronic medical records or medical equipment.
Hospitals depend on reliable communication to coordinate referrals, patient appointments, staffing and administrative decisions. When those systems become unavailable, employees must find other ways to exchange important information.
British Hospitals Maintain Patient Care Despite Disruption
Hospitals across Britain's National Health Service also experienced significant communication problems.
King's College Hospital in London reported that staff could not send or receive emails through Outlook. However, the hospital confirmed that patient services, planned procedures and operations were continuing as scheduled.
University College London Hospitals issued similar guidance, telling patients to contact clinics by telephone when communication was urgent.
Portsmouth Hospitals University NHS Trust reported problems with staff email and administrative systems. It warned that some non-urgent requests could take longer than usual while emphasizing that emergency care remained available.
The National Pharmacy Association also cautioned that patients might experience delays obtaining prescriptions. Some pharmacies and healthcare providers were unable to exchange information through their usual electronic communication channels.
Sir Ciarán Devane, chief executive of the NHS Alliance, said clinical and operational systems appeared to be functioning effectively despite the email disruptions. He explained that healthcare organizations had contingency arrangements to maintain services.
The distinction is important because losing email access does not automatically mean that hospitals cannot treat patients. Nevertheless, communication failures can increase workloads, delay administrative processes and complicate coordination among healthcare professionals.
Government Offices and Courts Report Problems
The outage also disrupted public services, including local governments, police departments and courts.
The City of Tampa, Florida, announced Friday that the disruption was affecting email communication between city employees, residents and outside organizations. Officials warned that some messages might be delayed or fail to reach their intended recipients.
However, Tampa confirmed that government offices remained open and were operating on their normal schedules. Telephone services, walk-in assistance and emergency 911 operations continued functioning.
City officials said Microsoft expected full service restoration within 48 hours. Residents with urgent questions were encouraged to contact departments directly by telephone.
In Britain, a trial in Manchester was interrupted because of the technology problems. Judge Maurice Greene sent jurors home after delays made it difficult to continue proceedings.
Some British police services also experienced problems receiving crime reports through online systems. Residents were advised to use telephone services for urgent matters.
Government agencies in Singapore, Japan, Greece and Norway reported disruptions to some operations, particularly email communications.
The incidents demonstrated how public agencies can experience operational difficulties even when essential emergency services remain available.
Microsoft Identifies Server Problems Behind Outage
Microsoft initially reported that parts of its infrastructure were experiencing unusually heavy demand. Engineers later determined that the pressure resulted from servers unexpectedly becoming unavailable.
When those servers stopped responding, remaining systems were forced to handle additional traffic. The resulting strain contributed to connection failures across several Microsoft 365 products.
Microsoft subsequently identified a technical problem that occurred during an upgrade following a recent network change. The company said its recovery efforts involved restarting affected servers, redistributing traffic and gradually restoring capacity.
Engineers also paused certain deployments and configuration changes while investigating the disruption.
The company said there was no indication that the outage resulted from a cyberattack or malicious activity. It also stated that the incident was unrelated to artificial intelligence agents.
By Friday, Microsoft reported improvements in email processing and access to affected services. However, restoring access did not immediately eliminate every problem.
Some email messages remained delayed because systems needed additional time to process accumulated traffic. Customers were warned that normal access could return before all pending communications had been delivered.
Disruption Revives Memories of 2024 CrowdStrike Incident
The widespread interruption brought renewed attention to the July 2024 CrowdStrike outage, which disrupted computers running Microsoft Windows around the world.
That earlier incident was caused by a defective software update from cybersecurity company CrowdStrike, rather than a failure of Microsoft's cloud services.
Hospitals, airports, banks and other organizations experienced serious problems when affected Windows computers crashed. Some healthcare facilities postponed procedures, diverted ambulances and temporarily returned to paper documentation.
The November 2026 outage was different because it primarily affected cloud-based communication and productivity services. There was no evidence that it caused the same widespread shutdown of hospital computers.
Nevertheless, both incidents illustrated the vulnerability of organizations that depend heavily on interconnected technology systems.
When several essential tools rely on the same infrastructure, one technical failure can disrupt multiple services simultaneously. Having alternative communication methods can help organizations continue operating during unexpected interruptions.
Recovery Continues as Organizations Assess Disruption
By Friday afternoon, several affected healthcare organizations reported improving conditions.
Cambridgeshire and Peterborough NHS Foundation Trust said its Microsoft services were operating normally by 4:15 p.m. local time. Leicestershire Partnership NHS Trust also reported that the problems had been resolved, although some administrative delays could continue while outstanding messages were processed.
Other hospitals advised patients to continue attending scheduled appointments and to use telephone contact when urgent communication was necessary.
Microsoft continued monitoring service availability while its engineers addressed remaining connection problems and delayed messages.
The company had not established a confirmed worldwide total of affected users. The full operational and financial impact on hospitals, government agencies and businesses also remained unclear.
Although many essential services continued functioning, the outage exposed how strongly everyday operations depend on reliable digital communications. Organizations affected by the disruption must now determine whether their backup procedures are sufficient when a major technology provider becomes unavailable.