When I roll out Copilot for Microsoft 365, one question comes up almost immediately: "Should we let Copilot use web search?" In many tenants this turns into a showstopper fast, particularly once the data protection officer or the works council gets involved. The worry is always the same. Are we sending sensitive prompts or document data out of our Microsoft 365 environment to Bing or the public internet?

Only the generated query leaves the Microsoft 365 boundary

This is the point I make in every one of these discussions. With Copilot web search (web grounding) enabled, the user's full prompt or document never leaves the Microsoft 365 service boundary. Copilot builds a new, abstracted search query from the prompt and sends only that query to Bing Web Search. For privacy, that's the part that matters most. Your internal data stays inside Microsoft's core secure environment, and the official Copilot privacy documentation confirms this.

To make it easier to picture, I put together a simple flowchart of what actually goes from Microsoft 365 to Bing when Copilot runs a web search:

direction LR
user["User prompt"] --> copilot["Copilot (M365 Service)"]
copilot --> query["Generated web search query"]
query --> bing["Bing Web Search"]
bing --> copilot
copilot --> user

Figure: Only the generated search query leaves the Microsoft 365 service boundary for Bing Web Search. The full prompt and any document content stay inside.

DPOs and works councils need the contractual difference explained clearly

People get this distinction wrong a lot. Copilot doesn't send documents, but it does send a generated, sometimes paraphrased fragment of what the user wants to know outside the Microsoft 365 boundary. That has consequences, because Bing search falls under different contractual terms than Microsoft's core cloud services. For the core services Microsoft acts as a processor. Bing Web Search, on the other hand, is governed by the Bing Web Search API SLA. You should definitely record this in your data protection impact assessment and discuss it openly.

The approach that has worked best for me is a short FAQ-style explanation for DPOs and works councils that lays out how the data flow and the contractual coverage differ. It builds trust, and it helps everyone see when web grounding is useful and where it stops being appropriate.

Practical tip: In the meeting with the works council or DPO, do a live demo and switch web search on and off in Copilot. People see the difference between Bing-assisted answers and answers based only on internal data right away.

A cloud policy controls Copilot web search, and I test it before rollout

The setting is the Allow web content in Copilot policy in the Microsoft 365 Apps admin center, which you'll find at config.office.com under Cloud Policy. A lot of tenants still have it at Not Configured. In that case users may see a toggle in their Office apps and can decide for themselves.

When I want to see exactly what the setting changes, I usually test it like this:

  • Enable or block the policy for a test group
  • Update the Office desktop apps so the new Cloud Policy applies
  • Give Copilot a prompt that obviously needs web content (e.g., "What's new in Windows 11 24H2?")
  • Check whether the Copilot answer includes source citations from the web
  • Look in the app settings to see whether the web search option is visible and enabled

For the documentation (and for every DPIA), I always record:

  • Who made the decision, and when
  • Which user groups it affects
  • The business case and scenarios for allowing or blocking web search
  • The contractual differences between Bing and M365 core
  • The controls and transparency in place (auditing, monitoring, user communication)

Most concerns about web search turn out to be misunderstandings

In real projects, most of the worries end up being overblown. No confidential document ever goes to Bing, because Microsoft built the system specifically to prevent that. Even so, web search isn't the right choice everywhere. Highly regulated sectors and users who handle strictly confidential data are the obvious examples. If you need full control, turn web grounding off for everyone, or at least for the sensitive groups. More innovative organizations often go for a phased pilot instead, with the DPO and IT closely involved and clear communication from day one.

Transparency works better than anxiety

The risk from Copilot web search is manageable, provided you understand the technical boundaries and document what you decide. Talking to the works council and DPO early and openly, and explaining the technology clearly, makes the whole Copilot rollout go much more smoothly. I've found that a live demo of Copilot with and without web search clears up the risks and benefits better than any policy memo. If you want to go deeper into getting your tenant ready for Copilot, I wrote about the difficult parts here: Copilot for Microsoft 365: The real challenge is your tenant.