Microsoft Outlook remains down for many users after more than ten hours of disruption, with the company admitting its fix is not working as planned.
The outage began around midday Thursday Eastern Time and has persisted through Friday morning in Asia and Europe.
Microsoft confirmed the issue centres on Exchange Online, the platform powering Outlook email, calendars, and contacts.
Reports peaked at over 130,000 users on Downdetector, with complaints spanning the Americas, Asia, and Australia.
Microsoft attributed the disruption to unexpectedly unavailable servers and elevated infrastructure load across multiple regions.
In a blunt update, the company said remediation efforts were "not taking as expected" and that it was seeking alternative solutions.
Some restored servers reportedly failed again once traffic resumed, prolonging the recovery.
Teams, SharePoint, Copilot, and Defender XDR were also affected, along with AI connectors used by OpenAI and Anthropic.
Businesses and government agencies reported significant disruption, with some rescheduling earnings reports and suspending services.
Microsoft has not provided an estimated restoration time, advising users to monitor its service health page for updates.
Administrators can track incident EX1550543 in the Microsoft 365 admin center for tenant-specific progress.
The outage began around midday Thursday Eastern Time and has persisted through Friday morning in Asia and Europe.
Microsoft confirmed the issue centres on Exchange Online, the platform powering Outlook email, calendars, and contacts.
Reports peaked at over 130,000 users on Downdetector, with complaints spanning the Americas, Asia, and Australia.
Microsoft attributed the disruption to unexpectedly unavailable servers and elevated infrastructure load across multiple regions.
In a blunt update, the company said remediation efforts were "not taking as expected" and that it was seeking alternative solutions.
Some restored servers reportedly failed again once traffic resumed, prolonging the recovery.
Teams, SharePoint, Copilot, and Defender XDR were also affected, along with AI connectors used by OpenAI and Anthropic.
Businesses and government agencies reported significant disruption, with some rescheduling earnings reports and suspending services.
Microsoft has not provided an estimated restoration time, advising users to monitor its service health page for updates.
Administrators can track incident EX1550543 in the Microsoft 365 admin center for tenant-specific progress.
