Short answer
For most organisations, Microsoft 365 Copilot can be used safely, but how safe depends far more on the state of your Microsoft 365 environment than on Copilot itself. The underlying technology is reasonable. The risk usually comes from existing permissions and oversharing, which Copilot then makes much easier to stumble across.
What Copilot does with your data
This guide is about Microsoft 365 Copilot: the licensed version your organisation buys, used by staff signed in with their work (Microsoft Entra ID) account. That distinction matters, and it is worth being precise about.
For Microsoft 365 Copilot, Microsoft states that it operates under Enterprise Data Protection: your prompts and Copilot’s responses are not used to train the underlying AI models, and your business data is not shared with other customers or made public. Copilot also respects your existing Microsoft 365 permissions and sensitivity labels: it can only use content the signed-in user is already allowed to open.
That last point is the one that matters most for security, and it works both ways.
Make sure staff are using the right Copilot
There is more than one thing called Copilot, and they do not all handle data the same way. Microsoft’s consumer Copilot privacy FAQ is clear that the free, consumer version behaves differently: by default it can use conversations to help train Microsoft’s AI models (users can opt out), and it stores conversation history. The protections above apply to Microsoft 365 Copilot used with a work account, not to the consumer app signed in with a personal account.
In practice, safe adoption includes making sure staff use the licensed Microsoft 365 Copilot signed in with their work account, and understand they should not paste confidential material into a personal or consumer AI tool. This is where it connects to wider AI governance .
The real risk: Copilot makes existing oversharing instant
Because Copilot can only see what a user can already see, the real question becomes: what can your users already see?
In most organisations that have run Microsoft 365 for a few years, the honest answer is “more than anyone realises”. Files shared with “everyone” long ago, SharePoint sites with broad access, Teams and mailboxes with loose membership, documents nobody ever tidied up: all of it is technically accessible, but in practice hard to find by hand. Copilot removes that friction. Ask it the right question and it will calmly summarise a document somebody forgot was open to the whole company.
Copilot does not create the oversharing. It just makes it effortless to surface. That is why a Copilot rollout is, underneath, an access and information-governance exercise rather than an AI project.
What to check before you turn it on
A sensible Copilot readiness review usually looks at:
- where files, sites and Teams are shared more broadly than intended;
- “anyone with the link” and company-wide sharing that is no longer needed;
- whether sensitivity labels are used for genuinely confidential material;
- administrator and over-permissioned accounts;
- guest and former-staff access that was never removed.
None of this is exotic. It is the same access hygiene that supports Cyber Essentials and a well-configured Microsoft 365 tenant. Copilot simply raises the stakes for getting it right.
A sensible way to roll it out
Start with a small pilot group rather than switching it on for everyone. Before that, review and tighten broad sharing and label the material that genuinely needs protecting. Watch how Copilot is used during the pilot, and widen access once you are confident that what people can reach is actually what they should reach. Pair it with brief guidance for staff on what they should and should not put into any AI tool.
Where this fits with your wider security
The work that makes Copilot safe is the same work that improves your security generally: tighter access, clearer ownership of data and sensible Microsoft 365 configuration. If you are already preparing for Cyber Essentials or have had a Microsoft 365 security review , much of the groundwork will overlap.
How Be Secure Cyber can help
We can review your Microsoft 365 access and configuration before a Copilot rollout, either as a one-off Microsoft 365 security review or as part of ongoing vCISO support . The aim is simple: when Copilot surfaces information, it should only ever be information the person should already have.
Speak to us about a Copilot readiness review.