Summary
- Microsoft 365 Copilot Researcher is retiring the dedicated Sites control for users enabled for Frontier.
- Users will no longer maintain a website list in the Researcher prompt UI; instead, they can reference preferred sites by name or URL directly in prompts.
- Existing tenant-level web search governance continues to control whether Researcher can use web content.
- No new admin settings are being introduced, and no administrator configuration change is required.
- Update user guidance and internal documentation that references the Sites control.
Microsoft is retiring the dedicated Sites control in Microsoft 365 Copilot Researcher for Frontier users by late September 2026. Users will no longer manage a separate website list, but can still specify preferred URLs directly in their prompts. Administrators do not need to configure any new settings, but should update internal documentation and notify affected users about this workflow change before the retirement date.
Administrator impact: No direct administrator action is required.
End user impact: Users will no longer use a dedicated Sites control in Researcher and must specify preferred websites directly within their prompts.
Score rationale: This is a feature retirement that requires minor documentation updates and user communication, but involves no technical administration.
The Sites control in Microsoft 365 Copilot Researcher for Frontier users will be retired by late September 2026. Users can still specify preferred websites directly in prompts. No admin action or new settings are needed; existing web search controls remain unchanged. Inform users and update documentation accordingly.
Message ID: MC1478004
Primary Service: M365 Copilot
Admin Impact: Low
User Impact: Medium
Release Start: Unknown
Release End: Unknown
Published: 24 Sept 2026
Expires: 29 Oct 2026
Last updated: 24 Sept 2026
Service: Microsoft Copilot (Microsoft 365)
Category: Plan for change
Tags: User impact, Admin impact, Retirement
Rollout: September 2026
History
9/23/2026 Item Added to Message Center
Microsoft Message
We are retiring the Sites control in Microsoft 365 Copilot Researcher for users enabled for Frontier. Today, the Sites control allows users to enter and maintain a list of websites when creating a research request.
After this change, users can continue to guide Researcher to preferred websites by referencing website names or URLs directly in their prompts. For example: “Research this topic using information from contoso.com and fabrikam.com.”
This update simplifies the Researcher experience while modernizing the underlying platform. Existing tenant-level web search controls will continue to determine whether Researcher can use web content. Specifying website names or URLs in a prompt indicates a user’s preferred research scope and does not function as an administrator-managed allowlist or blocklist.
Rollout schedule
Retirement for Frontier (Worldwide): Beginning in late September 2026 and expected to complete in late September 2026
Impact on your organization
Who is affected
Users with a Microsoft 365 Copilot license who are enabled for Frontier and currently use Researcher
Platforms and services
- Microsoft 365 Copilot
- Researcher
- Frontier
What will happen
- The dedicated Sites control will be removed from the Researcher prompt experience.
- Users will no longer be able to add or manage websites through the Sites control.
- Users can continue to specify preferred websites by including website names or URLs directly in their prompts.
- Existing tenant-level web search settings will continue to govern whether Researcher can access web content.
- No changes are being made to administrator-configured website controls for Researcher with Computer Use.
- No new admin settings are being introduced.
- Existing web search governance and controls remain unchanged.
Action required and recommendations
No administrator action is required.
We recommend that you:
- Inform impacted users that the Sites control is being retired.
- Update any internal training or documentation that references the Sites control.
- Remind users that website preferences can continue to be specified directly within Researcher prompts.
- Review existing web search settings if you want to confirm how web content is governed in your organization.
Compliance considerations
No compliance considerations identified, review as appropriate for your organization.