Microsoft outage live updates: What to know as Outlook, 365 and other apps remain down

In an update late Thursday night, Microsoft said it is continuing efforts to improve server stability to improve traffic flow as it works to repair an hourslong outage impacting its products for millions of people around the world.

Outlook is among several Microsoft products that have been unavailable to users for most of the day.

In an update at 8:36 p.m. PST, Microsoft 365 said it was observing partial recovery access across regions where it has rolled out changes, however, the recovery has not been sustained. It said it is continuing to review what additional actions can be taken to improve overall stability.

In another update at 9:01 p.m. PST, Microsoft 365 said, "We're engaged in multiple workstreams to alleviate impact, address our current blocker, and returning portions of service infrastructure back to a healthy state."

As of 6 p.m. PST Thursday, Microsoft said it's seeing "positive results" with its efforts to restart the affected servers causing a major outage.

Full Status Update:
We're seeing positive results with our efforts to restart affected infrastructure. We're actively monitoring the performance of these to verify stability which will support improved availability. Remediation actions will be expanded as we confirm stability with the changes applied.

Microsoft has revealed the cause of the massive outage of its 365 services that has hindered users across the world.

In a status update on Thursday night, Microsoft said its investigation found "a process on the affected servers responsible for establishing secure connections becomes overwhelmed, causing the servers to stop processing requests."

Microsoft is still actively working to resolve the issue and is expected to provide an update at 6 p.m. PST.

Full status update:

"Our investigation has found that a process on the affected servers responsible for establishing secure connections becomes overwhelmed, causing the servers to stop processing requests. We're preparing a configuration change to address this behavior that can be applied across all affected servers, and we're validating it on a subset of servers before applying it more broadly alongside restarts of the affected infrastructure. In parallel, we've begun reverting a recent network configuration change that correlates with the start of impact and are monitoring to determine whether this contributes to recovery. The temporary traffic limitations we previously described are now in effect in specific locations. We're monitoring the affected servers in those locations to confirm whether they remain stable while handling a narrower set of connections, after which we'll gradually reintroduce additional traffic."

Users of Microsoft's 365 suite may experience a gradual recovery as the company reports some server stability amid a major outage.

In a post on X, Microsoft says it's beginning to return a portion of affected servers to the service, and they remain stable so far.