Microsoft said on Saturday, November 14, that it had fully restored services after a global Microsoft 365 outage that began on Thursday and continued to disrupt users into Friday.
Reports of problems with Outlook, Teams and Copilot came from more than 70 countries and territories, according to outage-tracking service Downdetector, though the number of users affected remains unknown.
The disruption reached public agencies and essential services as well as companies relying on Microsoft software.
In Britain, a trial in Manchester was suspended, police reported difficulties receiving online crime reports, and the National Pharmacy Association warned of potential prescription delays as health services experienced communication problems.
The BBC reported that British cyber minister Liz Lloyd said the impact on critical frontline services, including emergency calls, was limited, and that the country's transport network was not disrupted.
Government agencies in Japan and Singapore also reported problems, while OpenAI and Anthropic said their connections to Microsoft 365 tools were affected, according to the Associated Press.
For businesses, the failure prevented some users from sending or receiving email, while others struggled to load their inboxes.
Microsoft attributed the incident to an issue introduced during an earlier network-capacity upgrade that emerged following a subsequent network change.
It said there was no indication of a cyberattack or involvement by artificial-intelligence agents.
Engineers worked to bring unexpectedly unavailable servers back online and restored capacity gradually to avoid further instability.
In a service-health update reproduced by Japan's THERS Account Help Center, Microsoft said earlier on November 14 that it was monitoring a backlog of emails accumulated during the outage.
The update noted that service access could recover before email delivery and processing had fully caught up, highlighting a distinction between restored access and completed message delivery.
Microsoft has said it plans to publish a full post-incident review.
The disruption also renewed questions about institutional reliance on a small number of cloud providers.
Rob Demain, chief executive of cybersecurity firm e2e-assure, told the BBC the outage highlighted how heavily businesses and essential services depend on large technology companies.