Can’t Access Outlook Emails due to Microsoft 365 Outage? A Guide to Offline Access

On November 12, 2026, many Microsoft Outlook users experienced a major service outage. The outage affected users across the world, primarily in the US and Asia-Pacific region, including Australia, India, and Japan.

Users reported problems accessing the Outlook, sending or receiving messages, and accessing various Microsoft 365 services. According to the monitoring website – Downdetector, more than 130,000 users reported problems with Outlook.  

The issues are primarily related to the Exchange Online. Microsoft acknowledged the disruption and began investigating connectivity problems affecting Exchange Online mailboxes. The company also shared updates through its Microsoft 365 Status account on X.

The company stated, “We are aware and investigating reports of users experiencing issues with Microsoft 365 services, primarily issues with Exchange Online.”

“We appreciate our customers’ patience while we work to restore services as soon as possible,” it added.

What Happened during the Microsoft 365 Outage?

The disruption was not limited to the Outlook application. Users also reported problems connecting with multiple Microsoft 365 services. Per the Microsoft’s Service Health Status page, features of the Microsoft 365 services that interact with Exchange Online and email services are impacted. These include Microsoft Teams, Microsoft 365 Admin Center, Copilot, SharePoint Online, OneDrive, Defender for Office 365, Microsoft Purview, and various others, creating difficulties for organizations that depend on these services.

Microsoft also clarified that elements of those services that do not rely on connectivity with Exchange Online remain functional.

What Caused the Microsoft 365 Outage?

According to Microsoft, the problems with infrastructure are responsible for the disruption rather than a sudden increase in user traffic. During its investigation, the company found out that some servers had become unresponsive, shifting additional workload onto the remaining infrastructure and increasing its load. The company also indicated that a component responsible for processing health checks might also be causing the issue, while affected servers were experiencing increased processor usage.

What Mitigation Steps Microsoft is Taking?

To mitigate the outage and disruption, Microsoft has redistributed connection traffic across its infrastructure worldwide, paused deployments and configuration changes, and restarted affected servers. The company also tested an alternative health-check method and started applying it more broadly.

On its Service Health Status page, it said, “As part of our ongoing efforts to advance the recoverability of our frontend servers, we’re evaluating traffic controls that can be applied to increase capacity and stability. This includes traffic optimization actions such as traffic throttling, protocol adjustments, and failover routing intended to improve stability in active regions. In parallel, we’re expanding internal testing to track activity within a contained environment to improve traffic monitoring and issue detection capabilities.”

“Once mitigated, we will provide full details of the root cause, defense-in-depth repair items, and more within a Post-Incident Report,” it added.

What Steps you should Take?

Organizations, which are relying on Microsoft 365, the major challenge is restore the email communication, until the Microsoft fix the issue and restore the services. However, in the meantime, you should take the following steps:

• Do not switch from the Outlook desktop application to the Outlook on the web as it is also affected.
• You can check Microsoft’s service health dashboard. You can monitor the Exchange Online incident EX1550543 and the broader Microsoft 365 incident MO1550821 via the Microsoft 365 admin center.
• You should avoid doing unnecessary changes in configuration. As Microsoft has already identified that issues are within its infrastructure, reinstalling the Outlook application or changing email settings doesn’t resolve the problem.
• As Outlook is facing issue when connecting to the server, don’t repeatedly sign in or reset your password.
• You should consider using other messaging services for urgent work.

Microsoft 365 Outage: How to Extract Emails and Other Data from an OST File

During the Exchange Online outage, your mailbox data is not lost. It stays on Microsoft’s servers but Outlook can’t connect to it. If your Outlook account is set up with Cached Exchange Mode, a copy of your mailbox data is stored on your system in Offline Storage Table (OST) file.

Due to unavailability of the server, your OST file becomes inaccessible. However, you can recover the data from the file by using a professional OST to PST converter tool, such as Stellar Converter for OST. This tool can extract data from inaccessible or orphaned OST files and save them in PST format. This tool can also export the data from OST file directly to a live Exchange Server or Microsoft 365 account. The tool can help you access previously synchronized mailbox data without depending on the Exchange Online.

Conclusion

The Microsoft 365 outage on November 12, 2026, disrupted Outlook and other services, preventing many users from accessing their mailboxes and sending or receiving emails. Microsoft has been working to fix the issue. In the meantime, it is important that you can safeguard your data stored in the Outlook data file (OST). You can convert the OST file to PST format by using Stellar Converter for OST. This allows you to access and preserve previously synchronized emails, attachments, contacts, calendar items, and other data. So, you’ll be ready to restore your mailbox data to Outlook, when normal functionality is restored.