Microsoft 365 outage largely resolved after nearly 24 hours
Microsoft traced the failure to a fault introduced during an earlier network capacity upgrade, and says a full post-incident report is coming.
A Microsoft 365 outage that began around 1 p.m. Eastern on Thursday has largely been resolved after nearly 24 hours, with Microsoft saying the underlying fault is fixed and service is recovering across its platforms. Customers lost access to Outlook email and parts of Teams and Copilot, and Exchange accounts in Apple Mail were also hit, while calling and messaging mostly stayed up though some scheduling and calendar actions failed. Microsoft has attributed the failure to a problem introduced during an earlier network capacity upgrade that surfaced after a recent network change, and has ruled out a cyberattack or AI agents as the cause. Restoration was staged gradually to keep it stable, and the company has promised a full post-incident report once its review is finished. Businesses, schools and governments worldwide were affected, and Japanese offices reportedly fell back on fax machines during the disruption.
Why it matters
For organisations that rely on Microsoft 365 for email and collaboration, the outage showed how a single fault in shared infrastructure can disrupt work across businesses, schools and governments at once. Microsoft has ruled out a cyberattack or AI agents, so the cause is an internal engineering error rather than an external threat. Reports from Japan of offices reverting to fax machines show how far some workplaces depend on the service and how quickly they fall back on older tools when it fails. The full post-incident report will show what went wrong in the upgrade.
Series Microsoft 365 outage
- Microsoft 365 outage largely resolved after nearly 24 hours
- Microsoft Outage Hits Office, Teams, Copilot and Xbox Live as Fixes Lag
- Microsoft outage disrupts UK GPs, police and other public services
- Microsoft 365 outage leaves many users unable to reach Outlook mailboxes
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