Microsoft's 12-Hour Teams and Outlook Outage Halts Trades, Delays Earnings

A more than 12-hour outage of Microsoft Outlook and Teams disrupted businesses and governments worldwide on Friday, forcing some organizations back to fax machines and halting at least one bond repurchase in Europe.

Microsoft said server issues caused the failure. The outage also affected its Copilot AI assistant. The company said a broader rollout of software fixes was starting to stabilize the system. Microsoft said it was not aware of any malicious activity.

Outlook and Teams rank among the most widely used workplace applications, serving hundreds of millions of users. The outage blocked essential functions such as sending email, managing calendars and hosting virtual meetings.

Microsoft said the outage specifically hit features tied to Exchange Online, its cloud-based email and scheduling hub. Applications not connected to that service remained operational. Organizations hosting Microsoft services on their own servers, rather than in the cloud, were partly spared.

How far did the disruption reach?

The impact stretched from Australia to Japan and the United States. Government agencies, trading firms, airlines and listed companies all reported problems.

The incident ranks among the longest in Microsoft's history and marks the second disruption to its services this year. Microsoft shares fell 1.7% before the bell, lagging the broader market. The stock has gained roughly 8% so far this year.

Specific fallout included:

• Euronext, the European exchange operator, reported email disruptions.
• British insurer Aviva activated backups for its earnings calls.
• Danish shipping giant Maersk warned customers of delayed updates.
• Electric truck maker Workhorse Group rescheduled its results from Thursday to Nov. 16.
• Switzerland's Richemont briefly delayed its first-half results announcement on Friday.

Airlines were hit hard. India's IndiGo, Akasa Air and Air India said their email support services were affected. Carriers warned customers of communication lags.

What happened in financial markets?

The outage disrupted fund management at Taiwanese securities firms, life insurers and investment trust companies. One company canceled a bond repurchase transaction, a source familiar with the situation told Reuters. Another Taiwanese financial company resorted to using fax to confirm trades, a second source said.

U.S. artificial intelligence firms OpenAI and Anthropic also faced issues with Microsoft connectors.

How did governments respond?

In the United Kingdom, the outage hit the National Health Service and London's Metropolitan Police. A government spokesperson said officials were working with Microsoft to find a solution.

The lack of email access affected the Metropolitan Police's ability to report some crimes online, though its ability to respond to calls was not affected. NHS said its local services were turning to alternate measures such as separate IT systems or paper records.

In Australia, the spy agency and federal police were among the organizations caught in the outage. Cyber Security Minister Tony Burke said Microsoft does not suspect a cyber attack.

"The impact that they are dealing with ... is very much on email systems," the minister said.

Will customers leave Microsoft?

The incident deepens questions about global reliance on a handful of Big Tech companies that supply both the essential software and the cloud infrastructure that underpins it.

"The bigger worry is that this is not the first Microsoft 365 outage this year," said Josh Gilbert, a market analyst at trading platform eToro.

"If reliability starts to look like a recurring problem, it hands every IT department a reason to think twice before putting even more of their business in one provider's hands," Gilbert said.

Some analysts question whether such incidents can push customers toward rivals, citing the steep switching costs of replacing tools embedded deeply in daily operations.

Microsoft faced a 365 outage in January this year and another in October last year. Last month, an Azure cloud platform outage hit its productivity software suite across a range of industries worldwide.

With two major disruptions in 2024 and repeated cloud failures over 14 months, Microsoft now faces mounting pressure to prove the stability of its infrastructure before enterprise customers reconsider how much of their operations they entrust to a single provider.