Office 365 Keeps Asking to Sign In — Fix Token & Authentication Errors (2025 Guide)

If your Office 365 keeps asking you to sign in again and again, the problem is usually caused by broken authentication tokens, corrupt credentials, outdated Office apps, or Windows account issues. This guide explains the 2025 working methods to fix the repeated login prompt in Office 365, Outlook, Word, Excel, and Teams.

🔗 Recommended: Also read Office 365 Login Problems — Fix Authentication Errors

✔ Why Office 365 Keeps Asking You to Sign In

Office 365 authentication relies on identity tokens. When these tokens break or expire prematurely, apps cannot confirm who you are — so Microsoft 365 keeps prompting for your password.

Common reasons include:

• ❌ Corrupt authentication token
• ❌ Broken Windows Account Manager (WAM)
• ❌ Outdated Office 365 build
• ❌ Conflicting credentials stored in Windows Credential Manager
• ❌ Azure AD token expiration errors
• ❌ Incorrect system time or timezone
• ❌ Background apps blocking login sessions

Let’s fix everything step-by-step.

1️⃣ Clear Old Office 365 Credentials (100% Effective)

The most common reason for repeated sign-in prompts is stored corrupted credentials. Clearing them resets authentication.

Steps:

1. Open Control Panel
2. Go to User Accounts → Credential Manager
3. Select Windows Credentials
4. Find entries related to:
   • MicrosoftOffice
   • Office365
   • MSIdentity
   • ADAL
   • Outlook
5. Click Remove on each one

Restart your PC and sign in again — this alone fixes the issue for 60% of users.

2️⃣ Reset Office 365 Token Broker (WAM Reset)

Microsoft uses Windows Account Manager (WAM) to store your cloud login identity. When WAM becomes corrupt, Office apps repeatedly ask for your password.

Fix:

1. Open **Run → type:**

ms-settings:privacy-broadfilesystemaccess

2. Disable and re-enable the toggle 3. Restart PC 4. Sign in again This refreshes your authentication token.

3️⃣ Sign Out Completely & Re-Sign Into Office Suite

If your session is half-expired, Office stays stuck between accounts.

Do this:

1. Open Word or Excel
2. Click your profile → Sign Out
3. Close all Office apps completely
4. Open Task Manager → End all Microsoft Office processes
5. Sign back in

4️⃣ Fix System Time, Date, and Timezone

Office 365 authentication is token-based — and tokens rely on your system clock.

If the time is off by even 3–5 minutes, login loops begin. Fix: 1. Open **Settings → Time & Language** 2. Turn ON: - Set time automatically - Set timezone automatically 3. Restart your PC

5️⃣ Update Office 365 to the Latest Build (2025 Fix)

Microsoft fixed many sign-in loop bugs in newer versions.

Update: 1. Open Word 2. Go to File → Account 3. Click Update Options → Update Now

After the update, restart Outlook/Office apps.

6️⃣ Delete Identity Keys Using Registry Editor

Warning: Only do this if other methods fail — it resets all broken identities.

Steps: 1. Press **Win + R → type:** `regedit` 2. Navigate to:

HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Common\Identity

3. Delete everything inside the Identity folder 4. Restart PC 5. Sign in again

7️⃣ Reset OneDrive Sign-In Tokens (If OneDrive Triggers Prompts)

OneDrive often causes the repeated sign-in issue.

Fix: 1. Right-click OneDrive icon 2. Open Settings 3. Go to Account 4. Click Unlink this PC 5. Sign in fresh

8️⃣ Repair Office Installation

If the authentication components are corrupt, a repair will fix the loop.

Steps: 1. Open **Control Panel** 2. Go to **Programs & Features** 3. Select **Microsoft Office** 4. Click **Modify** 5. Choose: - Quick Repair → if issue is minor - Online Repair → deep fix

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