Sign-in & Login Problems

Fix a Blank Microsoft 365, Teams, or Outlook Sign-In Window

Emma Brown Oct 7, 2026 869 views

Question details

Users are unable to log into Microsoft 365, Teams, or Outlook desktop applications because the authentication prompt loads as a blank screen.

How to Fix a Blank Sign-In Window in Microsoft 365, Teams, or Outlook

Product: Microsoft 365, Teams, Outlook
Device & OS: Windows
Scenario: Attempting to authenticate and sign into desktop versions of Microsoft Office applications.
Observed behavior: A completely blank white or black pop-up window appears instead of the usual login fields, blocking access to the application, even though web sign-in works normally.

Before you start

Ensure you have your correct Microsoft account email and password written down, as you will need to re-enter them after clearing your system's cached credentials.

Solution 1Recommended

Clear Stale Credentials from Windows Credential Manager

Removing corrupted or outdated cached login data forces the Microsoft applications to generate a fresh authentication prompt.

Windows stores login tokens to keep you signed into apps. When these tokens become corrupted, they can interrupt the sign-in process and cause blank screens.

Close applications

Fully close all running Microsoft 365 applications, including Teams and Outlook. Ensure they are not running in the system tray.

Open Credential Manager

Click the Windows Start button, type 'Credential Manager' into the search bar, and press Enter to open it.

Locate Microsoft credentials

Click on 'Windows Credentials' and scroll down to the 'Generic Credentials' section to find entries starting with 'MicrosoftAccount' or 'msteams'.

Remove credentials

Click the drop-down arrow next to the relevant Microsoft credentials and select 'Remove'. Confirm the deletion.

Restart and sign in

Restart your Windows computer, open your Microsoft 365 application, and attempt to sign in again.

Clear Stale Credentials from Windows Credential Manager

Tip: Clearing credentials does not delete any of your documents, emails, or personal data. It only resets your login session.

Solution 2

Update or Reinstall the Affected Applications

Outdated applications, conflicting Office installations, or missing Windows updates can break the desktop authentication process.

Solution 3

Request Administrator Review (For Managed Devices)

If you are using a work or school device, enterprise security policies might be blocking the sign-in prompt.

Free Microsoft Office alternative

Switch to WPS Office for a Hassle-Free Desktop Experience

If complex authentication loops and blank sign-in screens in Microsoft 365 are disrupting your workflow, consider using WPS Office. It provides a lightweight, reliable desktop experience with high format compatibility, completely free from restrictive enterprise login issues.

1. Download the installer: Visit the official WPS Office website and download the free version for Windows.
2. Install the software: Run the setup file and follow the quick installation prompts.
3. Open your files instantly: Launch WPS Office to immediately open, edit, and save your existing Office documents.

Highly compatible with Microsoft Word, Excel, and PowerPoint file formatsLightweight installation with no complex background authentication services requiredFree to use with a familiar, easy-to-navigate user interfaceWorks flawlessly offline without requiring constant cloud sign-ins

microsoft office alternative - wps office

Frequently Asked Questions

Why does my Microsoft 365 sign-in work on the web but show a blank screen on the desktop app?

Web browsers handle authentication independently using their own cache and session management. Desktop applications rely on Windows-level authentication components like the Web Account Manager (WAM). A blank screen usually indicates a corruption or glitch in these desktop-level components, not an issue with your account itself.

Will uninstalling Microsoft 365 or Teams delete my files?

No. Uninstalling the desktop applications only removes the software framework from your computer. Your Word documents, Excel spreadsheets, and Outlook emails stored locally or on OneDrive remain perfectly safe.

What causes a blank sign-in window specifically in Microsoft Teams?

In Teams, this is often caused by outdated app versions, conflicting cached credentials in the Windows Credential Manager, or overly restrictive conditional access policies set by an organization's IT department.

Login & Account Issues