Microsoft Outage Hits 74 Countries, Disrupts Korean Businesses

A global Microsoft outage spread to 74 countries and territories within roughly an hour on Friday, disrupting operations at major Korean companies and leaving employees unable to access email, collaboration tools and the Copilot AI assistant for hours.

Downdetector, which tracks online service disruptions based on user reports, recorded more than 138,000 reports of Outlook problems in the United States at the peak, reached shortly after 1 p.m. Thursday local time. Reports also surged in the United Kingdom, India and New Zealand. Nearly three in 10 reports during the first two hours came from outside the United States.

The outage hit a core dependency of modern corporate work. Microsoft said some of its servers had unexpectedly gone offline, placing additional strain on the rest of its infrastructure, and that it had found no evidence of a cyberattack. The company said traffic was not the cause.

Which services went down?

The disruption affected multiple Microsoft services:

• Outlook, the company's email platform
• Parts of Teams, the messaging and meeting application
• Microsoft 365, the productivity suite including SharePoint document management
• Copilot, Microsoft's AI assistant

The impact varied by company depending on the services used. Some major Korean employers sent urgent companywide notices alerting employees to the outage and asking them to check which Microsoft services were affected. Some companies also circulated email notices identifying the services that were unavailable.

The failure carried over into third-party AI tools. OpenAI said new connections through its Microsoft connectors could fail and that some tools were not working as expected. Anthropic reported failures affecting its Microsoft 365 connector, including access to email, SharePoint files, Teams chats and calendars, as well as difficulties establishing new connections. The disruption potentially limited those services' ability to retrieve and work with business data.

How did Korean companies cope?

An information technology industry official said employees had turned to other messaging apps to keep some work moving, but the workaround offered only limited relief.

"Since we cannot use email, we are exchanging files through messaging apps. But some files cannot be sent that way, so certain tasks are on hold," the official said.

"We also cannot access shared calendars linked to employees' schedules, which is inconvenient. For now, we're focusing on tasks we can work on with the materials available."

The disruption was particularly severe for businesses that rely on Microsoft's cloud-based collaboration tools. A retail industry official said the outage left her team struggling to communicate with suppliers and coordinate work across departments, as email services and SharePoint became inaccessible.

"We need to communicate with our business partners, but we cannot even check the emails we've received from them or who sent what. And even if I send an email through personal mail, if they use Outlook, they can't check it at all," the official said.

"Shared spreadsheets used to compile work across the company are also managed through SharePoint on Microsoft 365, and those services are down as well, making it extremely difficult to work."

An official of a major business group said the outage had called into question Microsoft's reputation as a global IT giant and market leader. The official tied the criticism directly to the company's positioning in the productivity software market.

"As a company that prides itself on driving workplace productivity and efficiency, Microsoft should feel a greater sense of responsibility for leaving businesses and users around the world struggling with disruptions throughout the day due to flaws in its own quality and service management systems," the official said.

Could affected businesses claim compensation?

Beyond questions of corporate responsibility, the outage could expose Microsoft to potential compensation claims from affected businesses. Attorney Lee Joo-heon of law firm Songyul said a damages claim is legally conceivable, even without intent to harm.

"From a legal standpoint, a claim is certainly possible in theory. Even if there was no intent, negligence could still be established," Lee said.

The obstacle, he said, is proving that the disruption caused measurable financial losses and determining how much compensation could be sought.

"In Korea, damages are generally awarded in monetary form, so the amount of loss ultimately has to be calculated (financially)," Lee said. "For large companies, daily revenue does not necessarily decline simply because their operations are disrupted. The key will be determining how much damage they suffered over the hours they were affected."

Asked whether Microsoft had compensation arrangements for affected customers, Microsoft Korea said the local office had not received any related information from its headquarters.

"We have not received any information from our headquarters regarding compensation, so we have nothing further to share at this point," its official said.

What did Microsoft say about the cause?

Microsoft attributed the outage to servers unexpectedly going offline, which put additional strain on the rest of its infrastructure. The company ruled out a traffic surge as the trigger and said it had found no evidence of a cyberattack.

Charles Lamanna, Microsoft's executive vice president of Copilot, Agents and Platform, addressed the disruption on social media.

"We regret that today's outages caused disruptions for our customers, and we are working to address the issue," Lamanna wrote. "For now, I can confirm that there is no indication this is the result of malicious or cyber activity."

The company said it was redistributing traffic across its global infrastructure and bringing affected servers back online to restore capacity. The first attempts at recovery did not succeed. Microsoft said its initial measures had not performed as expected, prompting a search for alternative approaches.

"We've monitored the status of the changes applied to improve serviceability and confirmed they're not taking as expected," Microsoft said. "We're identifying alternate workstreams that can be applied to increase capacity in the face of sustained traffic management imbalances."

Why does the outage matter beyond Korea?

The incident demonstrates how much corporate workflow now runs through a single vendor's cloud. When Outlook, Teams, SharePoint and Copilot fail at once, employees lose email, shared files, calendars and AI assistance simultaneously, and the workarounds — personal messaging apps, postponed tasks — cover only a fraction of daily operations.

The outage also reached the AI layer that Microsoft and its partners have built on top of that infrastructure. OpenAI's and Anthropic's connectors into Microsoft 365 failed alongside the underlying services, meaning businesses that connected AI tools to their email, files and chats lost that capability too.

The scale was global from the start. Reports began climbing in the United States shortly after 1 p.m. Thursday local time, and within roughly an hour the outage had spread to 74 countries and territories, with the United Kingdom, India and New Zealand among the countries reporting surges.

The compensation question remains open. Microsoft Korea has no guidance from headquarters on remedies for affected customers, and any Korean damages claim would turn on the calculation Lee described: how much measurable loss a company suffered over the specific hours it was affected. Whether Microsoft offers a formal response on compensation, and whether its alternate capacity workstreams fully restore service, will determine how quickly this incident fades for the businesses that lost a working day to it.