Outlook outage: Microsoft announces full restoration of service, losses could reach $500 million for affected businesses

Microsoft said Saturday that services had been fully restored to Teams, Outlook and its other products, ending a global outage that paralyzed online communications for businesses and governments for more than 24 hours. "We have successfully completed our efforts to resolve the issue underlying the incident and have restored service to still affected customers and regions," the company said on

Outlook and Teams are among the most used business applications, with hundreds of millions of users. This outage prevented users from performing essential tasks such as sending emails, managing calendars, and hosting virtual meetings. It affected governments from Australia to Japan to the United States, caused delays at brokerage firms, prevented some companies from publishing their financial results and forced airlines to warn their customers of communication delays, according to public statements.

Organizations that host Microsoft services on their own servers, rather than in the cloud, have been relatively unscathed. Second outage this year This outage, reports of which began to multiply around 5:25 p.m. GMT on Thursday according to Ookla, is one of the longest in Microsoft's history and the second interruption of its services this year. Microsoft said the outage specifically affected features related to Exchange Online - its cloud-based email and calendaring platform - leaving unconnected apps operational.

The incident reinforces questions about the world's reliance on a handful of tech giants that provide both essential software and the cloud infrastructure that underpins it. It also highlighted the reliance on Microsoft's business software, with outage reports peaking as employees began their workday in Asia and Europe, according to Ookla, Downdetector's parent company. Downdetector has recorded more than 7.4 million reports across the world, peaking at nearly 20,000 per minute, more than 1,500 times typical levels.

“This shows how much of the workday now relies on messaging and collaboration tools from a single vendor,” said Luke Kehoe, chief industry analyst at Ookla. Disruption and financial losses from the outage could result in numerous claims, but the overall impact on insurers is expected to be limited, said Mario De Cicco, vice president of European financial institutions at Morningstar DBRS. De Cicco estimated global insured losses from the incident at $300 million to $500 million, far lower than the $400 million to $1.5 billion financial cost of the 2024 CrowdStrike outage, which crippled more than 8 million Windows-based computers and caused widespread disruption.

Microsoft also faced an outage of its 365 services in January this year and October last year. Last month, the company reported an outage in its Azure cloud platform that affected its productivity software suite and various lines of business across the world. “The most worrying thing is that this is not the first Microsoft 365 outage this year,” said Josh Gilbert, market analyst at eToro.

"If reliability starts to emerge as a recurring problem, it gives all IT departments a reason to think twice before handing over an even larger share of their business to a single vendor." Some analysts, however, question whether such incidents could push customers toward competition, given the high migration costs of replacing tools so deeply integrated into daily operations. Use of faxes A British government spokesperson said it was working with Microsoft to find a solution to the outage which affected organizations such as the NHS and the London Metropolitan Police.

The inability to access email and other services has impacted the Metropolitan Police's ability to report some online crimes, although its ability to respond to calls has not been affected. The NHS has said its local services are looking to alternatives, such as using IT systems or paper records. For businesses, the repercussions have been widespread.

European stock exchange operator Euronext reported email disruptions, British insurer Aviva activated its backup systems for its financial results conference calls and Danish shipping giant Maersk warned customers of delays in updates. US AI giants OpenAI and Anthropic also encountered issues with Microsoft connectors, which were later resolved, while Indian airlines IndiGo INGL. NS, Akasa Air and Air India reported that their email support services were affected.

The outage also disrupted fund management at Taiwanese brokerages, life insurers and fund management companies. One of these companies even went so far as to cancel a bond buyback operation, a source familiar with the matter told Reuters. Another Taiwanese financial company had to resort to faxing to confirm its transactions, a second source said.

In the United States, electric truck manufacturer Workhorse Group postponed the publication of its results on Thursday until November 16, while Swiss group Richemont briefly delayed the announcement of its first-half results on Friday. In Australia, where intelligence services and the federal police were among the organizations affected by the outage, cybersecurity minister Tony Burke said Microsoft did not suspect a cyberattack. “The impact they are facing… mainly concerns electronic messaging systems,” the minister added.

Machine-translated from French