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Fix Power BI Gateway Rejecting Windows Authentication for Local Excel Files

Maira Mehtab Sep 24, 2026 869 views

Question details

The user is unable to refresh a published Power BI semantic model because the on-premises data gateway rejects the Windows authentication credentials for the connected local Excel files.

Product: Power BI / Excel
Device & OS: not provided
Scenario: Publishing and refreshing a Power BI semantic model connected to local Excel files via an on-premises data gateway.
Observed behavior: The data gateway rejects the entered Windows username and password as invalid, preventing the dataset from authenticating and refreshing.

Before you start

Ensure that your on-premises data gateway is fully updated and running on a machine that remains powered on and connected to the network where the Excel files reside.

Solution 1Recommended

Verify Gateway Account Permissions and Credential Formatting

Check that the credentials are formatted correctly and that the gateway service account has explicit read access to the local Excel files.

Power BI gateways often reject credentials if the username format does not include the domain or machine name, or if the underlying service account lacks Windows folder permissions to read the local file.

Format Username Correctly

When entering credentials in the Power BI Service data source settings, use the fully qualified domain format. Enter 'DOMAIN\Username' for domain accounts or 'MachineName\Username' for local accounts.

Check File Path Access

Ensure the gateway is running under a Windows account that has direct file system access. Right-click the folder containing your Excel files, select Properties, go to the Security tab, and verify the gateway account has Read permissions.

Re-enter Credentials

Navigate to the gateway settings in Power BI Service, locate your Excel data source, and carefully retype the Windows password to rule out typos or recently expired passwords.

Microsoft Community Support: If the issue persists, post the complete error logs and gateway setup details in the Microsoft Fabric Community Power BI forums, as this is a specific Microsoft Power BI configuration issue.

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Frequently Asked Questions

Why does Power BI say my Windows credentials are invalid for a local Excel file?

This typically happens if the username is not entered in the 'Domain\Username' format, the password has expired, or the service account running the gateway lacks permissions to access the local file path.

Can I use a personal gateway instead of an enterprise gateway for local Excel files?

Yes. If you are the only one using the dataset and the host machine stays powered on, a Personal Gateway can be used without configuring complex Windows authentication for specific data sources.

How do I grant file access to the Power BI gateway account?

Right-click the folder containing your Excel files, select Properties, go to the Security tab, click Edit, and add the Windows service account (e.g., 'NT SERVICE\PBIEgwService') with Read permissions.

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