Security Policy Errors

Fix Microsoft 365 Untrusted Content Security Warning

Khadija Khan Sep 25, 2026 869 views

Question details

Users encounter a security warning prompt when trying to open files or access content hosted on SharePoint and OneDrive in Microsoft 365.

How to Fix the Microsoft 365 Security Warning About Untrusted Content

Product: Microsoft 365
Device & OS: not provided
Scenario: Opening network files or accessing organizational content hosted on SharePoint or OneDrive via Microsoft 365 applications.
Observed behavior: Microsoft 365 displays a warning stating 'This content presents a potential security issue. Do you trust this content?' and restricts immediate access to the file.

Before you start

Before adjusting any security settings, verify that the file or the SharePoint/OneDrive link you are attempting to open is from a known, secure source within your organization to prevent potential malware or phishing attacks.

Solution 1Recommended

Add the Source Domain to Trusted Sites in Internet Options

Adding the specific SharePoint or OneDrive URL to your system's Trusted Sites list resolves the warning for safe, organizational content by telling Microsoft 365 the location is secure.

Microsoft 365 applications rely on Windows Internet settings to determine if a network location is safe. If your organization's SharePoint or OneDrive domain is not explicitly trusted, Office will display a warning out of caution.

Open Internet Options

Press the Windows key, type 'Internet Options' into the search bar, and press Enter to launch the Internet Properties window.

Navigate to the Security Tab

Click on the 'Security' tab at the top of the window, then click on the 'Trusted sites' zone icon (the green checkmark).

Access the Sites List

Click the 'Sites' button located just below the zone selection to open the Trusted sites configuration dialog.

Add the Domain

In the 'Add this website to the zone' field, enter the domain of the SharePoint or OneDrive site (for example, https://*.sharepoint.com) and click 'Add'.

Save and Restart

Click 'Close' on the Trusted sites window, click 'OK' on the Internet Properties window to apply the changes, and then restart your Microsoft 365 application.

Add the Source Domain to Trusted Sites in Internet Options

Organizational Policies: If the 'Add' button is greyed out, your IT administrator may centrally manage these settings via Group Policy. You will need to contact your IT support team to have the domain added.

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Frequently Asked Questions

Why does Microsoft 365 flag my company's SharePoint files as untrusted?

Microsoft 365 enforces strict security protocols to prevent malicious scripts from executing. If your organization's SharePoint domain isn't explicitly listed in your system's Trusted Sites, Office applications may flag the content as a precaution.

Can I disable the 'Do you trust this content' warning entirely?

It is not recommended to disable security warnings entirely as it exposes your system to risks. Instead, you should manage warnings safely by adding only known, trusted domains to your Trusted Sites list or configuring Trust Center settings specifically within the Office apps.

Does this security warning mean my computer has a virus?

No, this specific warning is a preventive measure triggered by accessing content from network locations or the internet that haven't been explicitly designated as secure. It does not indicate an active malware infection on your computer.

Microsoft Office Security Issues