Can we turn off Copilot’s web search grounding?

That’s a genuine concern, and you’re wise not to treat “grounded in the web” as a free upgrade with no control plane. Convenience and boundary discipline pull in opposite directions here.

Here’s what’s happening. When web search is enabled, Copilot may send a generated search query — a few words derived from the prompt, not the full prompt, not whole Microsoft 365 files, and without Entra identifiers — to the Bing search service to enrich the answer. Prompts and responses stay in Microsoft 365 under enterprise data-protection terms; the generated Bing queries sit under different Product Terms commitments (not used to train foundation models or build ads profiles, treated as customer confidential) but the Microsoft DPA does not apply to those Bing queries, and HIPAA / EU Data Boundary carve-outs don’t either. Admins control this with the Allow web search in Copilot policy in Cloud Policy service for Microsoft 365 (also surfaced via Copilot Control System settings). Options include enable for Copilot and Copilot Chat, disable for both, or disable in Copilot Work mode while leaving Web mode / Chat enabled. Users can further flip a Web content toggle off when admins leave search on; if admins disable the policy, the toggle is greyed out. Leave the policy unconfigured and web search is generally on by default in commercial tenants (GCC/DoD default off until you enable it).

This is First Law for data leaving the house: don’t put organisational context into a web-grounding path unless you can see how the query comes out — policy, audit, and a clear GRC decision. 12 Panes puts Security → GRC in Steady before “better answers from the web” becomes everyone’s default.

Practical options:

1. Policy by cohort. Disable web search for regulated groups; enable for knowledge workers who need current public facts. Use Cloud Policy scoping, document the rationale, and review Purview DSPM / audit for generated queries. Best default for mixed-risk organisations.
2. Tenant-wide off until GRC signs off. Simple; protects the boundary; reduces answer quality for public-market and news-style prompts. Reasonable Wave 0 posture.
3. Tenant-wide on, rely on user toggles. Fast adoption; uneven compliance — people forget toggles. Weak for regulated work.
4. Turn off all optional connected experiences instead. Broader blast radius across Microsoft 365; Learn warns this restricts more than web search alone. Specialist hammer, not your first tool.

The caution: Web search citations in Copilot Chat can show the exact generated queries for a short window — useful for coaching, not a substitute for admin audit. Researcher / Cowork behaviour follows the Work-mode policy choice. Blocking web search does not fix oversharing inside the tenant; that remains permissions, RCD, labels, and DLP.

I’d suggest a short GRC note: who may use web grounding, which Cloud Policy setting applies, how you’ll audit queries, and what users should expect when Work mode is web-off. Then turn the dial once — not in a panic after the first board question.

You’re asking the right questions. Steady before scale means the web is an explicit choice, not an ambient leak path.

DIGITAL SKILL WORKS LTD / 12 PANES · You ask, we answer