Microsoft Stabilises Servers Six Hours Into Global 365, Defender and Intune Outage

Microsoft said it had stabilised swathes of crashing servers six hours into a sweeping global outage that affected Microsoft 365, Microsoft Defender and the remote management toolkit Intune. The Stack reported that engineers redistributed traffic and isolated servers without identifying a cause.

How Microsoft Responded To The 365 Outage

In a series of status updates throughout Thursday, Microsoft first suggested that elevated load on a portion of infrastructure might be to blame and began redistributing connection traffic across its broader worldwide infrastructure. It then identified that a number of servers were failing automated health checks and becoming unavailable, straining adjacent infrastructure. Several hours into the outage, the company said it had "not identified any recent change correlated with the start of impact."

Shortly after 10pm GMT, five hours in, engineers said: "We're opening all available pathways to restore service, as our actions taken thus far have not provided the anticipated relief." They said a core process on affected servers was becoming overwhelmed, causing capacity loss, and that they were evaluating whether isolating traffic within each region might let affected regions recover independently. Shortly before midnight GMT, Microsoft said it had begun returning a portion of the affected servers to service and that they were remaining stable so far, with limited recovery in some regions.

What ThousandEyes Saw During The Outage

Network monitoring firm ThousandEyes said that beginning around 17:30 UTC it observed availability issues affecting Microsoft 365 services globally, according to akta.pro company records. Users attempting to access Microsoft Outlook and other Microsoft 365 services encountered connection resets, connection refusals, response timeouts and HTTP server errors, and significant traffic loss in Microsoft's network was observed during the incident.

Earlier Microsoft Outage Reports

On November 12, Global News reported that Microsoft 365 was experiencing connectivity issues affecting over 100,000 users worldwide, with reports spiking after noon Eastern, and that the company said a portion of infrastructure was experiencing elevated load across multiple regions. FOX 2 reported that Ferguson police postponed a virtual town hall about the Flock camera accountability portal due to a Microsoft outage, and that Microsoft reported nearly 120,000 users affected. MarketWatch reported that Workhorse Group postponed its third-quarter earnings release and investor call to the following week, citing Thursday's Microsoft outages, and now plans to report on Monday, November 16, after market close.

Workhorse Group's New Earnings Date

Workhorse Group plans to report third-quarter earnings on Monday, November 16, after market close, according to MarketWatch.