Key facts
- Microsoft said routine automated checks took some servers offline, overloading the remaining ones with traffic.
- Microsoft said it restored services gradually because of the scale of demand, which lengthened the recovery.
- Microsoft said the outage was a technical failure rather than a cyber-attack and apologised for it.
- Email systems for the US House of Representatives and Australian intelligence agencies were knocked out, the report said.
- Court systems in Singapore and airline support desks in India were disrupted, the report said.
- Microsoft said it was reviewing what went wrong and expected the findings to inform prevention steps.
A Microsoft 365 disruption lasted more than 22 hours and affected services including Outlook, with issues reported across more than 70 countries, the BBC reported on November 13, 2026. Microsoft said routine automated checks took some servers offline, overloading the remaining ones with traffic, and that engineers restored services gradually.
A Microsoft spokesperson said that "given the scale of demand" the company restored services gradually, and that "while this took longer, it helped ensure a stable restoration." Microsoft apologised for the disruption and said it was caused by a technical failure rather than a cyber-attack. The company said it was reviewing what went wrong, with the findings expected to inform steps to prevent a similar disruption.
The fallout reached public institutions and businesses. Email systems for the US House of Representatives and Australian intelligence agencies were knocked out, and court systems in Singapore and airline support desks in India were disrupted, according to the report. Around 430 million people globally use Microsoft 365.
Flora Hamilton, executive director of the Small Business Charter, said the outage was a "stark reminder" of how much firms "rely on digital systems" such as Outlook "to keep their operations running." Walter Pasquarelli, an AI strategist, told the BBC the outage had "put their vulnerabilities and dependence in plain sight" for governments, businesses and critical infrastructure.
Gergely Orosz, a former software engineer at several major tech companies, said such outages were not unheard of but the time Microsoft took to recover was unusual. He said a solution could be to split services by region, as Amazon's AWS cloud service does.