Global Microsoft disruption hits US Congress, UK health services

• Microsoft executive Charles Lamanna said there is currently no indication that the failure was caused by malicious or cyber activity.

The outage has disrupted the US House of Representatives, municipal governments across the United States, and the UK's National Health Service, prompting Microsoft to extend its email timeout window to 48 hours to protect delayed messages.

A rolling global Microsoft outage extended into a second day on Friday, leaving millions of office workers, government agencies, and public services without access to Outlook email, Microsoft Teams, Copilot, and other core workplace tools.

The disruption, which began around 1 p.m. ET on Thursday, quickly spread worldwide, with outage tracker Downdetector recording user reports across 74 countries and territories within roughly an hour.

By early Friday, Microsoft reported seeing "early signs of stabilization" and "incremental improvement," though full service had not yet been restored.

In a statement posted early Friday, Microsoft Copilot Corporate Vice President Charles Lamanna said there is currently no indication that the outage is the result "of malicious or cyber activity".

Microsoft later explained that a number of servers became unexpectedly unavailable after failing automated checks, leaving the remaining infrastructure overloaded as traffic shifted, and causing some restored servers to become unresponsive again once user traffic returned.

To prevent undelivered messages from bouncing during the prolonged recovery, Microsoft announced around 4:15 a.m. ET Friday that it was extending its "email timeout window" to 48 hours so mail servers continue holding delayed messages while service recovery progresses.

The disruption has affected banks, courts, airlines, and government institutions worldwide, even forcing at least one publicly listed company to postpone a quarterly earnings call:

• US government and cities: The US House of Representatives said its users were impacted and said engineers were working directly with Microsoft, while city governments across the United States advised residents to call local offices instead of emailing.
• UK healthcare and public services: In the United Kingdom, disruptions to the National Health Service (NHS) email and communications systems affected hospitals, ambulance trusts, and general practitioners, threatening delays to patient prescriptions.
• Workplace applications: Outlook and Exchange Online experienced the most severe outages, leaving users unable to send or receive emails.

Microsoft Copilot was largely unable to load chats or pull data from emails and calendars, while Teams users faced trouble scheduling calendar-linked meetings, though direct chats and existing calls continued working for many.

Core offline functions in Word, Excel, and PowerPoint remained operational, though cloud printing, SharePoint file sharing, and recent-file lists were disrupted.