Microsoft M365 outage stretches past 12 hours as fixes keep failing

Microsoft 365 services tied to Exchange Online remain disrupted more than 12 hours after an outage began on Thursday at around 18:00 UTC. Users have been unable to access email, attend Teams meetings, use cloud PCs, consult Copilot, or fully use another 15 hosted services. Microsoft says services that do not need Exchange Online remain functional while it continues recovery work.

Impact on users and services

In Australia, the outage has been called the "Microsoft long weekend," because it has been pervasive enough to make Friday a write-off at organizations that rely on Redmond's online services, especially Exchange Online. Microsoft says the outage impacts Microsoft 365 services "that interact with Exchange Online and email services." The company initially blamed the outage on a "problem that's causing servers to fail automated health checks and become unavailable."

Fixes and recovery attempts

Microsoft thought it had found a fix but admitted that "Actions taken thus far have not provided the anticipated relief." In the hours since, the situation has not improved markedly, and Microsoft is still struggling to restore service. Its status feed described applying infrastructure capacity improvements, monitoring changes that were not taking as expected, reviewing traffic flows and affected infrastructure, identifying alternate workstreams, observing partial recovery that was not sustained, and scaling up virtual machines while machines were stuck in a bad state that prevented changes from syncing. Microsoft's latest update says it is continuing to pursue multiple workstreams to pinpoint the underlying cause of the traffic influx and advance recoverability of backend servers, while taking a measured approach to identify and repair affected infrastructure and tracking results.

Cyberattack possibility

Microsoft has not completely ruled out a cyberattack, although its wording changed during the incident. As of 04:11 UTC, the company said it could find "no indication this is the result of malicious activity." An update time-stamped 05:46 UTC stated, "As of now, we are not aware of any malicious activity that is causing this incident." Microsoft's latest status update does not suggest the outage will be over soon.

Earlier coverage: Multiple Microsoft 365 services experience outage on Nov. 12

Sources: The Register · BBC · CNN