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How to Fix Microsoft 365 Sign-In Error: Authentication Broker Is Missing
Question details
Users are unable to sign into Microsoft 365 applications due to a missing or damaged Authentication Broker component.
- Product
- Microsoft 365
- Device & OS
- Windows
- Scenario
- Attempting to sign in to Microsoft 365 desktop applications or utilizing multifactor authentication.
- Observed behavior
- The sign-in process fails, often displaying an error indicating that the Authentication Broker is missing.
Ensure you have administrator access to your Windows device and an active internet connection before troubleshooting system services and accounts.
Update Windows and Reconnect Your Account
This is the most effective method to restore the missing Authentication Broker by updating system components and refreshing account credentials.
The Authentication Broker relies heavily on core Windows OS services. When these become outdated or encounter glitches, Microsoft 365 sign-in fails. Updating Windows and re-adding your Microsoft account typically resolves the problem.
Open Windows Settings, navigate to 'Update & Security' (or Windows Update), and click 'Check for updates'. Install any pending updates and restart your computer to ensure system components are current.
Press Win + R on your keyboard, type 'services.msc', and press Enter. Scroll down to find 'Microsoft Account Sign-in Assistant' and 'Web Account Manager'. Ensure both services are running and their startup type is set to Automatic or Manual.
Go to Windows Settings > Accounts > Access work or school. Click on your affected Microsoft 365 account and select 'Disconnect' to remove the cached credentials.
In the same 'Access work or school' menu, click 'Connect' to add your Microsoft 365 account back. Once added, open your Microsoft 365 application and attempt to sign in again.
Try WPS Office for a Hassle-Free Offline Experience
If Microsoft 365 sign-in and authentication issues are disrupting your workflow, WPS Office offers a lightweight, reliable alternative. It doesn't rely on complex background authentication brokers for basic document editing, ensuring you stay productive without interruption.
- 1. Download and Install WPS Office: Visit the official WPS website to download the free installation package and follow the on-screen instructions to install it on your Windows device.
- 2. Open Your Existing Files: Launch WPS Office and directly open your existing Word, Excel, or PowerPoint documents without needing to sign in or deal with authentication brokers.
- 3. Enjoy Offline Editing: Continue your work seamlessly with full offline editing capabilities and save your files locally or to your preferred cloud storage.
Frequently Asked Questions
What is the Authentication Broker in Windows?
The Authentication Broker (often associated with the Web Account Manager) is a built-in Windows component that securely manages user credentials and handles the sign-in processes for Microsoft applications and connected services.
Why does the Microsoft 365 sign-in fail with this error?
This error generally occurs when the underlying Windows services responsible for handling credentials become corrupted, disabled, or outdated, preventing the Office apps from communicating with Microsoft's authentication servers.
Will reinstalling Microsoft 365 fix the Authentication Broker missing error?
Not necessarily. Because the Authentication Broker is a Windows Operating System component, repairing or updating Windows itself is usually required rather than just reinstalling the Office applications.
