Microsoft struggles to restore services: What actually happened and list of services affected

Microsoft is struggling to restore services after a widespread outage disrupted 19 of its products, including Outlook, Microsoft Teams, Copilot and several enterprise and security applications, affecting users across multiple regions.

Sequence of events

The disruption began with reports of users in the Americas being unable to access their Exchange Online mailboxes. It later spread to other regions, affecting several Microsoft 365 services that rely on the company's email infrastructure.

In a series of updates on X, Microsoft's official Microsoft 365 Status account said the problem was caused by several servers unexpectedly becoming unavailable, putting additional pressure on the remaining infrastructure.

"We determined the elevated load isn't driven by an increase in traffic, but by a number of servers being unexpectedly unavailable; straining the remaining infrastructure," the company said.

Microsoft said it was restarting affected servers, shifting traffic to other parts of its global network and increasing computing capacity to restore services.

However, some servers that had been restored became unresponsive again after receiving traffic, prompting it to examine diagnostic data and temporarily restrict certain types of traffic reaching affected infrastructure.

Microsoft also identified an overwhelmed core process on affected servers that was causing capacity loss.

"We're opening all available pathways to restore service, as our actions taken thus far have not provided the anticipated relief," the company said in another update.

The company has since reported partial recovery in some regions.

“We're observing partial recovery across regions in which we've applied these adjustments; however, these actions aren't resulting in sustained recovery, so we're reviewing what additional actions we can take to improve overall infrastructure stability,” it said.

Microsoft said it was scaling up virtual machines to increase capacity and reduce infrastructure load. It was also attempting to force synchronisation of recent network changes on machines stuck in a bad state, which was preventing the changes from being applied as expected.

The company said users could experience gradual recovery as capacity is restored and their applications reconnect.

Microsoft has not identified a recent change that directly coincided with the beginning of the disruption.

19 Microsoft services impacted by the outage:

1. Exchange Online: Users may be unable to access mailboxes through Outlook on the web, desktop applications and other connections. Email delivery may also be delayed.

2. Microsoft 365 admin center: Administrators may be unable to load certain pages.

3. Microsoft 365 apps: Users may face problems viewing recently used files.

4. Microsoft 365 Apps Admin Center: Cloud Update, Cloud Policy and Inventory services are affected.

5. Microsoft 365 Education: Assignments, Reading Progress and Speaker Progress may be disrupted.

6. Microsoft 365 Copilot: Users may be unable to access Copilot Chat or receive responses. Its ability to retrieve work emails, calendars and files may also be affected.

7. Microsoft Defender for Office 365: Security features such as Safe Links, Safe Attachments, Quarantine and Threat Explorer may encounter failures.

8. Microsoft Defender XDR: Users may be unable to access certain pages and features of the Defender security portal.

9. Microsoft Fabric: Some users may encounter errors while exporting reports to PDF or PowerPoint or opening protected files.

10. Microsoft Graph: Requests involving emails, calendars and contacts may time out, affecting certain connected applications and services.

11. Microsoft Intune: Device enrolment, check-ins and compliance policy operations may be intermittently affected.

12. Microsoft Planner: Users may encounter problems while managing plans and tasks.

13. Microsoft Purview: Data protection, compliance, information security and data classification features may be affected.

14. Microsoft Teams: Core features such as calls, meetings, group chats and channel messages remain largely functional. However, calendar access, meeting scheduling, invitations and some other features may fail.

15. Microsoft To Do: The app may fail to load or users may encounter errors while using it.

16. Power BI: Users may intermittently be unable to export reports carrying certain security labels to PDF.

17. SharePoint Online: Features dependent on Exchange Online may be affected, but direct access to stored files remains functional.

18. Universal Print: Users may encounter errors while submitting print jobs or accessing administrative features.

19. Windows 365: Some customers using Microsoft Purview Customer Key may be unable to connect to their Cloud PCs.