Microsoft 365 global outage cripples Outlook, Teams and Copilot for hours
Starting November 12, Microsoft 365 experienced a widespread global service disruption affecting Outlook (web and client), Exchange Online, Teams, SharePoint Online, OneDrive and Microsoft 365 Copilot, with Americas users hit first—many unable to send or receive email or facing severe delays. Per Downdetector, by around 1:30 PM ET more than 120,000 users reported being unable to access Outlook, with thousands more reporting Teams failures.
Confirmed
- Microsoft officially attributed the incident to overloaded infrastructure components and core processes causing capacity loss, leading to connection errors.
- Recovery measures included isolating parts of the infrastructure, restarting affected components, shifting traffic and rebalancing resources, then gradually restoring traffic to verify stability.
Unconfirmed
- Per a tip relayed by @tomwarren, the root cause was a release/deployment that spiked server CPU usage and pushed racks into maintenance mode, triggering cascading failures; this comes from an internal leak—Microsoft's official account only confirmed overload-driven capacity loss.
Why it matters
- The incident swept across the entire Microsoft 365 suite; @ZealousidealPin3444 noted that AI assistants like Copilot went down along with the underlying services, highlighting how deeply coupled AI features and cloud infrastructure can become a single point of failure.
- @Kyrannio and @m4 both noted Americas Exchange Online users were hit first, showing how a regional infrastructure failure can quickly cascade into a global event.
2026-11-13 ~ 2026-11-13 · 33 related posts
Primary sources
- Microsoft Outlook down worldwide as M365 infrastructure buckles under load — tomwarren · 2026-11-13
- Microsoft data center outage sparks jokes about servers 'going on protest' — SuB8u · 2026-11-13
- Microsoft 365, Teams, Copilot All Down at Once: Your AI Has One Big Off Switch — Zealousideal_Pin3444 · 2026-11-13
- Microsoft 365 outage hits Exchange, Teams and Copilot across the Americas — Kyrannio · 2026-11-13
- Widespread Microsoft outage hits Outlook with 120,000+ user reports, Teams and Copilot also affected — asusarla · 2026-11-13
- [source] Microsoft Outlook outage: botched rollout spiked CPU, triggered cascading rack failures — tomwarren · 2026-11-13
- Microsoft 365 outage knocks Outlook, Teams, SharePoint and Copilot offline — Dave_Maynor · 2026-11-13
- Microsoft, AWS, Google and more hit by simultaneous mass outage — zainhas · 2026-11-13
- Microsoft can't fix Outlook outage because engineers are getting too many Authenticator prompts — Kyrannio · 2026-11-13
- Outlook outage traps a CEO who's feared migrating hundreds of GB of email for 14 years — mobileraj · 2026-11-13
- [source] Microsoft outage hits 130,000 users; developer warns of cloud dependency costs — esrtweet · 2026-11-13
- Microsoft outage drags on: servers re-crash under traffic, traffic types limited — Kyrannio · 2026-11-13
- Microsoft outage persists as company says it's 'rebuilding a subset of affected servers' — Kyrannio · 2026-11-13
- Microsoft outage strands office workers nationwide as critic invokes 'last days of Rome' — Kyrannio · 2026-11-13
- [source] Microsoft 365 outage drags on: restored servers go unresponsive again — Kyrannio · 2026-11-13
- Microsoft 365 outage hits Exchange Online, Copilot, Defender, Teams and more — Kyrannio · 2026-11-13
- Microsoft outage takes down Teams, SharePoint, Copilot for 6+ hours after server failure — justin_hart · 2026-11-13
- Massive Microsoft 365 outage: Outlook down globally, even Microsoft staff can't send email — Scobleizer · 2026-11-13
- Microsoft 365 outage: racks of servers failing health checks, all new deployments paused — rickasaurus · 2026-11-13
- Outlook outage so absurd a client refused to believe the service was actually down — Kyrannio · 2026-11-13
- Exchange Online outage: traffic still ~90% below normal after 6.5 hours, Microsoft struggling — kingslyj · 2026-11-13
- Microsoft still isolating M365 server outage, revises list of impacted services — SumitGup · 2026-11-13
- Microsoft Outlook hit by massive global outage, M365 email down worldwide — asusarla · 2026-11-13
- Microsoft 365 outage burns through a year's worth of four-nines uptime before lunch — justin_hart · 2026-11-13
- Microsoft 365 outage sparks migration threats: dev vows to move org off Microsoft to AI-managed open source — Scobleizer · 2026-11-13
- Microsoft 365 outage hits Exchange Online, Copilot and many services — seanmcdonaldxyz · 2026-11-13
- Microsoft 365 outage persists as first fix fails; new capacity workstreams underway — Kyrannio · 2026-11-13
- Microsoft outage hit 74 countries in an hour, Outlook reports spiked 2000x — CurieuxExplorer · 2026-11-13
- Microsoft mocked as outage explanation points to no reserve capacity — esrtweet · 2026-11-13
- Microsoft's outage explanation sparks mockery: returned servers "can become unresponsive again under load" — Kyrannio · 2026-11-13
- Microsoft 365 global outage hits day two as Outlook and Teams stay unstable — sidjustice_ · 2026-11-13
- Microsoft 365 outage worsens: Exchange Online fixes "not taking as expected" — Kyrannio · 2026-11-13
1 near-duplicate retellings: Kyrannio