Data Protection Issues

Fix Microsoft Purview Not Applying DLP Policies to On-Premises File Servers

Maira Mehtab Sep 28, 2026 870 views

Question details

Users are experiencing an issue where Microsoft Purview scans discover files on an on-premises file server, but Data Loss Prevention (DLP) policies are not applied.

Product: Microsoft Purview
Device & OS: not provided
Scenario: Registering an on-premises file server and configuring data source scanning for DLP compliance.
Observed behavior: Files are discovered during the scan, but DLP policies fail to apply, typically due to incorrect data source registration.

Before you start

Ensure you have administrative access to your Microsoft Purview portal and gather details about your Self-hosted Integration Runtime configuration.

Solution 1Recommended

Consult Microsoft Purview Specialists on Microsoft Q&A

Since registration, scanning, and DLP behaviors are highly specific to the Microsoft ecosystem, the most effective approach is to escalate the issue to official Microsoft support channels.

Microsoft Purview's integration with on-premises file servers involves complex configurations. When files are scanned but DLP policies aren't applied, it usually points to a mismatch in the Self-hosted Integration Runtime or an incomplete data source registration.

Gather environment details

Note down your Self-hosted Integration Runtime version, the specific type of registered data source, and the current scan status from your Purview dashboard.

Review policy configuration

Document your current DLP policy configuration. Ensure you do not include any sensitive or personally identifiable information in your notes.

Navigate to Microsoft Q&A

Open your web browser and go to the official Microsoft Q&A platform to prepare your support request.

Submit your question

Post your detailed query including the gathered details. Ensure you apply the 'Microsoft Purview' tag so that dedicated specialists can easily locate and investigate your issue.

Protect Sensitive Data: Never share actual file contents, passwords, or sensitive network topologies when posting on public forums like Microsoft Q&A.

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Frequently Asked Questions

Why does Microsoft Purview scan my files but fail to apply DLP policies?

This typically occurs when the on-premises data source is not registered correctly in the Microsoft Purview portal, which prevents the enforcement mechanism from recognizing the scope of the policies.

What information should I prepare before contacting Microsoft support for Purview?

You should prepare details about your Self-hosted Integration Runtime, the specific registered data source, your current scan status, and a summary of your policy configuration, taking care not to share sensitive data.

Can I use WPS Office to encrypt my local files before sharing them?

Yes, WPS Office provides built-in document encryption and password protection features, allowing you to secure individual Word, Excel, and PowerPoint files locally before they are uploaded to servers or shared.

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