Windows 11 March update breaks Microsoft account sign-ins in Teams, OneDrive, Edge, and more

Microsoft has confirmed that the March 2026 Windows 11 security update can block Microsoft account sign-ins in several apps, including Microsoft Teams Free and OneDrive. Affected users may see an error saying they need an internet connection even when the PC is already online.

The problem is tied to KB5079473, released on March 10, 2026, for Windows 11 versions 24H2 and 25H2. Microsoft says the issue affects sign-ins that use personal Microsoft accounts, while business sign-ins that use Microsoft Entra ID are not affected.

That matters because the bug can block access to core Microsoft services on consumer PCs. In its official release health note, Microsoft says the issue can also affect Microsoft Edge, Excel, Word, and Microsoft 365 Copilot whenever those apps need a Microsoft account sign-in.

For now, Microsoft has not posted a permanent fix. As of March 21, 2026, the company still lists the issue as a confirmed known problem on the Windows 11 release health dashboard.

What is causing the Windows 11 sign-in bug?

Microsoft says the problem appears when a device enters a specific network connectivity state after installing KB5079473. The result looks like a connectivity problem, but the company’s wording suggests the root issue sits in how Windows handles that post-update network state rather than in a real internet outage.

That explains why the error message feels misleading. Users can have a working internet connection and still get blocked from signing in to apps that depend on a Microsoft account.

Which Windows 11 versions are affected?

Microsoft lists the issue under Windows 11 versions 24H2 and 25H2. The March 10 cumulative update KB5079473 maps to OS builds 26100.8037 and 26200.8037 in Microsoft’s update history.

Affected platforms at a glance

Item	Details
Problem update	KB5079473
Release date	March 10, 2026
Affected Windows versions	Windows 11 24H2 and 25H2
Known affected apps	Teams Free, OneDrive, Edge, Excel, Word, Microsoft 365 Copilot
Account type affected	Microsoft accounts
Business impact	Entra ID sign-ins not affected
Status	Confirmed known issue

Data based on Microsoft’s release health and support pages.

Apps and features Microsoft says can fail

Microsoft explicitly names several apps, but the scope is wider than one or two products. The company says any feature inside an affected app that requires Microsoft account authentication can trigger the same error.

That means some users may still open an app but get blocked when they try to sync files, activate cloud features, load account data, or complete sign-in flows. Microsoft has not published a full app-by-app breakdown beyond the examples it listed.

Microsoft’s confirmed examples

• Microsoft Teams Free
• Microsoft OneDrive
• Microsoft Edge
• Microsoft Excel
• Microsoft Word
• Microsoft 365 Copilot

These examples come directly from Microsoft’s known issue note.

Microsoft’s current workaround

Microsoft says users should restart the device while it stays connected to the internet. According to the company, that restart should repair the connectivity state and help prevent the issue from returning immediately.

There is one catch. Microsoft warns that restarting the device without an active internet connection can push it back into the faulty state, which may bring the sign-in failure back.

What affected users should do now

• Confirm that KB5079473 is installed
• Connect the PC to the internet before restarting
• Restart Windows while staying online
• Try signing back into Teams Free, OneDrive, or the affected app
• Check Microsoft’s release health page for status changes

Those steps reflect Microsoft’s published workaround and support guidance.

Why this bug matters

This is not the kind of Windows bug most users can ignore. If OneDrive cannot sign in, file sync can stop. If Teams Free cannot sign in, chats and calls can become inaccessible. If Edge or Office apps ask for Microsoft account authentication at the wrong moment, that can interrupt regular work on a personal PC.

The impact looks smaller in enterprise environments because Microsoft says Entra ID authentication is not affected. That narrows the blast radius, but it still leaves home users, students, freelancers, and small teams using consumer Microsoft accounts in a bad spot.

It also lands at an awkward time. KB5079473 is a Patch Tuesday security update, which means many systems install it as part of routine monthly maintenance. Microsoft’s own support page says the update includes security fixes and other improvements, making this sign-in bug an unwanted side effect of a standard Windows rollout.

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