Microsoft Email Outage: Company Says ‘No Evidence of Malicious Activity’

Microsoft on Friday was still struggling to restore service to millions of Outlook and Exchange email users more than 18 hours after its servers crashed and became unavailable.

In an update on Microsoft’s Service Health Status page Friday morning, the company did not explain what triggered the catastrophic outage but said that it did not suspect a cyberattack or other foul play.

“At this time, we have no evidence of malicious activity associated with this incident,” the company said in the update at 6:11 a.m. ET on Nov. 13. “We will continue to treat this with urgency until full mitigation, and we will share a full Post-Incident Report with root cause and defense-in-depth actions after mitigation is complete.”

Outlook and other Microsoft 365 services that interact with the Exchange Online and email services remained largely unavailable. The issues began affecting Outlook at around 12:30 p.m. ET on Thursday; both individual users and enterprise customers have been unable to access their email since then. Outlook users have reported that they began receiving notifications of new emails, but that they still were unable to access their mailboxes.

On Friday, Microsoft said that “We’ve made additional progress toward service recovery, with recovery actions completed across portions of the affected infrastructure in the Asia Pacific region. Traffic is being gradually restored, and we’re seeing improvements in key customer scenarios, including mailbox access and delayed email processing. However, some users may continue to experience intermittent issues.”

The tech company continued, “Our focus is now on extending these recovery actions across affected infrastructure in other regions, while continuing stabilization efforts and adding supporting capacity to improve service consistency. Reducing email queues and backlogs remains a priority, and the extended 48-hour email timeout window remains in place to help protect delayed messages as delivery catches up.”

Features of multiple Microsoft 365 services that interact with Exchange Online and email services were affected. Those included Outlook, the Microsoft 365 admin center, Microsoft 365 apps (as users may be unable to view their recently used files); Microsoft Copilot 365; SharePoint Online; and Microsoft Teams (with respect to features that depend on Exchange Online, including calendar-related failures with scheduling, invites, viewing and meeting edits and creation of Live or Virtual events).