Microsoft says email queues 'approaching normal levels' as Outlook issues persist
Millions of users faced disruptions to Outlook and Microsoft 365 services due to infrastructure load issues.
Quick Look
- Microsoft services, including Outlook and Microsoft 365, are recovering after a 20-hour global outage caused by infrastructure load issues.
- The disruption affected governments, businesses, and healthcare providers worldwide, with no evidence of malicious activity.
AI-generated summary
Why It Matters
Microsoft experienced a major server infrastructure failure lasting over 20 hours, impacting global services. The company attributed the issue to unexpected server unavailability and elevated load.
Microsoft users began to regain email access on Friday amid one of the company's biggest-ever server issues that lasted more than 20 hours, causing disruption to millions of its customers.
Engineers scrambled to solve connectivity problems that began shortly before 1 p.m. ET on Thursday.
Email and calendar service Outlook, along with multiple Microsoft 365 services such as Sharepoint and Copilot, were largely down during the Asian business day on Friday, throughout the European morning and into the early U.S. hours. Numerous external services that connect with Microsoft products were also hit.
In an update at around 9 a.m. ET, Microsoft continued to warn that users may be unable to connect to multiple Microsoft 365 products, including Outlook on either web or desktop and many services that interact with email.
However, it said it was "continuing to see improvements in service availability, with email queues significantly reduced and approaching normal levels." It had previously given updates by region, with Asia Pacific services among the first to start normalizing.
Intermittent issues are expected as recovery efforts continue.
Engineering teams have been taking affected systems offline for fixes and bringing them back online in stages. They are prioritizing efforts to preserve emails delayed during the recovery process and reduce email queues and backlogs, extending the timeout window, whereby delayed emails continue to attempt delivery, to 48 hours to help protect messages.
Microsoft says it has not detected any malicious activity causing the outage, which it initially blamed on a traffic surge in part of its infrastructure and issues with a component responsible for processing server health.
The company said in its initial updates on Thursday that the connectivity problems related to infrastructure "elevated load across multiple regions," caused by a "number of servers being unexpectedly unavailable; straining the remaining infrastructure." Some servers were failing automated health checks, it said.
Microsoft shares were around 0.8% lower in premarket trade.
Governments and businesses in Asia-Pacific and Europe said they were monitoring the situation, which was causing widespread disruption.
The U.K.'s National Health Service said the outage was affecting some of its services but that patients should attend appointments as normal. Calls "may be subject to long waits" as a result of disruption to the organization, a hospital group serving South West London and the English county of Surrey said on X.
Earnings for Swiss luxury goods giant Richemont were slightly delayed on Friday due to the outage. Electric truck maker Workhorse Group, which was expected to report third-quarter results on Nov. 12, rescheduled the release to Nov. 16, citing business disruptions caused by the global Microsoft outage.
Air India said it had "temporarily rerouted" emails so it could continue to receive customer messages, adding that its flight operations were not affected.
Australian Home Affairs and Cyber Security Minister Tony Burke said in a press conference that Microsoft "believe they are dealing in some ways similar to what we saw with respect to CrowdStrike where there is an update that has gone awry," Reuters reported.
A fault with an update issued by cybersecurity company CrowdStrike caused one of the world's biggest IT system outages in 2024, hitting airlines, banks and more.
Microsoft reported in 2025 that Copilot, its collection of AI assistants and tools, had more than 100 million monthly active users.
The incident highlights a business "resilience and dependency issue that has been decades in the making," James Owen, managing partner of Digital Risks at consultancy Control Risks, said by phone.
"We have become, organizationally in the private sector and more broadly, increasingly dependent on a smaller segment of technology and infrastructure as critical to daily life and business activities."
"Organizations are becoming more aware through a geopolitical lens about what technologies they adopt, whether their services are provided by firms in the U.S., or China, or elsewhere, but this shows the importance of proper recovery planning in the case of an IT outage. That could be manual backups, protocols that do not require internet connection, investing in diverse suppliers and crisis management planning rehearsals," he said.
Amazon Web Services and Google users also reported outages on the site on Thursday.
Amazon wrote on X that services were "operating normally" and an "unrelated disruption elsewhere on the internet is prompting some inaccurate news reports." The company referred users to its health dashboard for "accurate data."
At 4 p.m. ET Thursday, Microsoft said it had "validated an alternative service health check method" that brought some affected servers back online.
"We're now applying this change more broadly," Microsoft wrote. "We're also preparing automated recovery systems to continually detect and restart unresponsive servers, to maintain service stability while this change progresses."
What to Watch
AI outlook — possibilities, not facts
Microsoft will release a detailed post-mortem report on the infrastructure failure.
Very likely · Within weeks
Open Questions
- What was the specific root cause of the server health component failure?
- Will there be long-term financial impacts on Microsoft's service level agreements?







