Sign-in & Login Problems

How to Fix Sign-In Problems in Teams, Outlook, and OneDrive

Chanuka Geekiyanage Sep 30, 2026 868 views

Question details

A user is unable to sign in to multiple Microsoft 365 applications while other users on the same network or system are unaffected.

Fix Sign-In Problems in Teams, Outlook, SharePoint, and OneDrive

Product: Microsoft 365 (Teams, Outlook, SharePoint, OneDrive)
Device & OS: Windows
Scenario: Attempting to log into desktop applications for Microsoft 365.
Observed behavior: The sign-in process fails exclusively for one user profile across several apps, occasionally triggering TPM error 80090016.

Before you start

Ensure you have your correct Microsoft 365 email and password readily available, and save any open documents before closing your applications.

Solution 1Recommended

Clear Cached Credentials and Office Identity Data

Resetting your local Office authentication state by clearing cached credentials is the most effective way to resolve persistent user-specific sign-in blocks.

When an individual user is blocked from signing in while others are not, the issue is typically caused by corrupted authentication tokens saved locally on that user's Windows profile. Clearing the Windows Credential Manager and resetting the registry identity forces the apps to fetch fresh authentication data.

Sign out and remove connected services

Open any functioning Office app (like Word or Excel), navigate to File > Account, click 'Sign Out' for all accounts, and remove any connected services listed. Close all Microsoft 365 applications completely.

Clear Windows Credentials

Click the Windows Start button, type 'Credential Manager', and press Enter. Select 'Windows Credentials', locate all entries starting with 'MicrosoftOffice', click on them, and select 'Remove'.

Remove Office identity from Registry

Press Windows Key + R, type 'regedit', and press Enter to open the Registry Editor. Navigate to HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Common\Identity, right-click the 'Identity' folder, and select 'Delete'.

Restart and sign in

Restart your computer. Open Microsoft Teams or Outlook and attempt to sign in again with your account credentials.

Clear Cached Credentials and Office Identity Data

Regarding TPM Error 80090016: If you receive error code 80090016 during sign-in, this indicates a Trusted Platform Module (TPM) malfunction. If clearing credentials does not work, your IT administrator may need to clear the device's TPM or re-register your device in Microsoft Entra ID.

Free Microsoft Office alternative

Switch to WPS Office for a Hassle-Free Document Experience

If persistent sign-in issues and authentication loops in Microsoft 365 are slowing down your workflow, consider switching to WPS Office. It offers a lightweight, completely free, and incredibly smooth alternative that lets you focus on your work without complex sign-in barriers.

1. Download the software: Visit the official WPS Office website and click the free download button to get the installer.
2. Install WPS Office: Run the downloaded setup file and follow the quick on-screen instructions to install the suite.
3. Open and edit files instantly: Launch WPS Office to immediately open your existing Microsoft documents, spreadsheets, and presentations.

No complex authentication loops required to access your basic local files.Highly compatible with Microsoft Office formats including Word, Excel, and PowerPoint.Lightweight installation ensures fast launch times and smooth performance on any PC.Familiar tabbed user interface makes migration seamless for existing Office users.

microsoft office alternative - wps office

Frequently Asked Questions

Why is only one user experiencing these Microsoft 365 sign-in issues?

This happens when the issue is localized to a specific Windows user profile. The authentication tokens or cached passwords saved in that specific user's Credential Manager or Registry have become corrupted, whereas other users on the system or network have healthy tokens.

Will clearing Windows Credentials delete my emails or OneDrive files?

No. Clearing the Windows Credential Manager only deletes saved passwords and authentication tokens used for logging in. Your actual emails, files, and account data remain securely stored on Microsoft's cloud servers.

What does TPM error 80090016 mean?

TPM error 80090016 indicates that your computer's Trusted Platform Module keys are out of sync with Microsoft's servers. This security feature failure prevents successful authentication and often requires clearing the TPM or having an admin unregister and re-register the device.

How do I access the Registry Editor safely?

You can access it by pressing Windows Key + R, typing 'regedit', and hitting Enter. Always be extremely cautious and consider exporting a backup of the registry (File > Export) before making any deletions.

Login & Account Issues