Sign-in & Login Problems

How to Fix Credential Invalid Error with Unexpected Substatus 6008

Natalie Taylor Sep 29, 2026 870 views

Question details

The user is unable to sign into Microsoft applications due to a credential validation failure returning substatus 6008.

How to Fix Credential Invalid Error with Unexpected Substatus 6008

Product: Microsoft Office
Device & OS: Windows
Scenario: Attempting to sign in to desktop applications like Microsoft Office, PowerPoint, or Teams using a personal, work, or school account.
Observed behavior: The sign-in process fails with the error message: 'The credential is invalid. Unexpected sub status (6008).'

Before you start

Before proceeding with cache clearing, test your account credentials by logging into office.com through a web browser to ensure your account is not locked or disabled by your organization.

Solution 1Recommended

Clear Credential Manager and AAD Broker Plugin Cache

This is the most effective method to resolve persistent authentication conflicts and clear corrupted sign-in tokens causing the 6008 substatus error.

Microsoft applications rely on the Azure Active Directory (AAD) Broker Plugin and Windows Credential Manager to store authentication tokens. If these tokens become corrupted or out of sync with your account status, you will encounter invalid credential errors. Clearing this cached data forces Windows to fetch fresh authentication credentials.

Sign out of all applications

Open any Microsoft applications you are currently signed into, including Word, PowerPoint, and Teams, and manually sign out of your account. Close the applications completely.

Clear the AAD Broker Plugin cache

Press Windows Key + R to open the Run dialog. Copy and paste %localappdata%\Packages\Microsoft.AAD.BrokerPlugin_cw5n1h2txyewy into the field and press Enter. Delete all files and folders inside this directory.

Remove Windows Credentials

Open the Windows Start menu, type 'Credential Manager', and press Enter. Click on 'Windows Credentials' and scroll through the list. Click on any entries related to MicrosoftOffice or your work/school account, and select 'Remove'.

Reconnect your Work or School account

Go to Windows Settings > Accounts > Access work or school. If your account is listed here, click on it and select 'Disconnect'. After a moment, click 'Connect' to sign back in and re-link your device to your organization.

Restart and sign in

Restart your computer. Open Microsoft Word or Teams and enter your email and password to sign in with fresh authentication tokens.

Clear Credential Manager and AAD Broker Plugin Cache

Work or School Account Sync: Disconnecting and reconnecting your account in Windows Settings often resolves underlying device-management policies that block application sign-ins.

Free Microsoft Office alternative

Avoid Sign-in Hassles with WPS Office

Tired of encountering complex Microsoft account errors and credential invalidation loops? WPS Office provides a lightweight, offline-friendly alternative that doesn't force you into restrictive authentication processes just to edit your documents.

1. Download and Install: Visit the official WPS Office website to download the free, lightweight installer for Windows.
2. Open Your Files: Launch WPS Office and directly open or drag-and-drop your existing Microsoft Office files into the workspace.
3. Edit Without Hassle: Start editing your documents, spreadsheets, and presentations immediately without worrying about unexpected substatus errors.

No mandatory complex sign-in loops to access basic document editing features.Fully compatible with Microsoft Word, Excel, and PowerPoint file formats (.docx, .xlsx, .pptx).Lightweight installation with fast startup times and minimal system resource usage.Free to use with a familiar, easy-to-navigate user interface.

Frequently Asked Questions

Why do I get the 'unexpected sub status (6008)' error?

This error typically occurs when there is a mismatch, corruption, or expiration in the locally cached authentication tokens for your Microsoft, work, or school account stored within Windows.

Does this credential error affect all Microsoft applications?

It generally affects desktop applications that rely on Microsoft's Azure Active Directory (AAD) broker, such as Word, Excel, PowerPoint, and Teams. Web-based access via a browser is usually unaffected.

Will removing entries from Credential Manager delete my files?

No. Removing entries from the Windows Credential Manager only clears saved passwords and temporary authentication tokens. Your local documents and cloud-stored files remain completely safe.

What if clearing the cache does not fix the 6008 error?

If the error persists, check if your organization has recently changed device compliance policies, verify that your account hasn't been disabled by your IT admin, or consider switching to a local Windows user account to test the application.

Login & Account Issues