Is Outlook Down? Microsoft Meltdown Leaves Millions Unable to Open Inboxes

Outlook remained down for many users worldwide on Friday 13 November, more than 12 hours after a server failure locked them out of their inboxes, and Microsoft said its fixes were not holding.

The company first flagged problems with Exchange Online mailboxes in the Americas shortly before 1 p.m. ET (6 p.m. GMT) on Thursday 12 November. It soon warned that the issue 'may affect Microsoft 365 service connectivity for users in any region.'

Outlook reports on outage tracker Downdetector climbed to nearly 130,000 soon afterwards, with complaints from 74 countries and territories within about an hour, according to the site. Some users could not open their inboxes, while others said emails were not being sent or received. Teams, Copilot, SharePoint, and OneDrive were also affected.

Microsoft has not said how many people were hit. Microsoft 365 had more than 450 million paid commercial seats as of January.

What Microsoft Says Went Wrong

Microsoft said a large number of servers had unexpectedly become unavailable after failing automated health checks, pushing extra load onto those still running. It said the strain was not caused by a rise in traffic and that a 'core process on affected servers is becoming overwhelmed, causing capacity loss.'

Microsoft paused all deployments and began restarting servers. Having initially said it found no recent change linked to the problems, it later began reverting a network configuration change that coincided with their onset.

Fixes Fail to Hold Overnight

Around 6 p.m. ET, Microsoft said it was 'returning a portion of affected servers to the service, and they remain stable so far.' It later warned those servers 'can become unresponsive again once they receive traffic.'

Downdetector reports for Outlook eased but stayed above 25,000 at about 10 p.m. ET. Shortly after 11:30 p.m. ET, Microsoft said it was seeing partial recovery in some regions, but 'these actions aren't resulting in sustained recovery.'

In the UK, Teams complaints on Downdetector spiked from around 6:15 p.m. on Thursday. Microsoft said servers restored several times overnight had crashed again.

By early Friday UK time, Microsoft had given no estimate for full recovery. It said Teams calls and meetings were largely working, but calendars, scheduling, and other features that rely on Exchange were not.

Police, Banks, and Governments Disrupted

In Australia, the intelligence agency ASIO and the Australian Federal Police were among the organisations caught up in the outage. Some Service NSW centres in regional New South Wales closed, and the state's online bail court was disrupted.

Australia's Home Affairs Minister Tony Burke said of Microsoft, 'They do not believe they are dealing with a cyber event.' He said the government had activated a provision in a memorandum of understanding signed with Microsoft in June that prioritises Australia's recovery from an outage.

Microsoft executive vice president Charles Lamanna also wrote on X: 'For now I can confirm that there is no indication this is the result of malicious or cyber activity.'

In Hong Kong, bankers at Morgan Stanley and Goldman Sachs told CNN their work had been disrupted. New York City Emergency Management warned that email to city agencies could be delayed. Banks, including ING in Australia, warned customers about scammers exploiting the outage.

The disruption follows a Microsoft 365 outage of almost 10 hours on 22 January and an Outlook failure lasting around 19 hours in July 2025.