Copilot doesn't create a new security risk on its own - it exposes one that was probably already there. Copilot searches and summarises across everything a user has permission to access, which means years of overly broad sharing and stale permissions suddenly become far easier to stumble onto than before. Here's what to check before turning it on.
Why Copilot Changes the Calculation
Before Copilot, a file shared too broadly sat there largely undiscovered unless someone happened to go looking for it. Copilot actively searches across everything a user can technically access and surfaces it in response to a prompt - meaning permissions that were technically wrong but practically harmless suddenly become a live exposure risk.
The Readiness Checklist
1. Audit External and "Anyone" Sharing Links
Run a full sharing report across SharePoint and OneDrive before rollout, and clean up anything shared more broadly than intended. See our guide on auditing external sharing in SharePoint and OneDrive for exactly how to do this.
2. Review General User Permissions
Beyond sharing links, check group memberships and folder-level permissions for stale or overly broad access. See our guide on auditing Microsoft 365 user permissions.
3. Set Up Sensitivity Labels
Microsoft Purview sensitivity labels let you classify and restrict access to genuinely sensitive content (client financial data, HR records) in a way Copilot respects. Without labelling, everything is treated as equally accessible to whoever technically has permission.
4. Review Data Loss Prevention Policies
Confirm DLP policies are active for sensitive data categories relevant to your business. See our guide on Microsoft Purview DLP explained for what this covers.
5. Confirm Licensing
Copilot is a separate add-on licence on top of an eligible Microsoft 365 plan - confirm current pricing and eligibility for your specific tenant plan before budgeting for rollout.
6. Plan a Staged Rollout
Pilot with a small, well-understood group first rather than enabling it organisation-wide immediately. This gives you a chance to observe what Copilot actually surfaces in practice and catch any remaining oversharing before wider exposure.
7. Set Staff Expectations
Copilot output can be confidently wrong (a general risk with generative AI tools), so staff need to understand it requires review, not blind trust, particularly for anything client-facing or compliance-relevant.
What Good Readiness Looks Like
By the time you roll out Copilot broadly, external sharing should be cleaned up, sensitive data should be labelled and protected by DLP policies, and a pilot group should have used it without surfacing anything unexpected. Skipping straight to a full rollout without this groundwork is where the genuine risk lies - not in Copilot itself.
Frequently Asked Questions
Will Copilot actually show a user files they couldn't already access?
No - Copilot respects existing permissions, it doesn't grant new access. The risk is the opposite: it makes existing overly broad permissions far more visible and usable than before, since Copilot can now actively surface and summarise content a user technically had access to but would never have manually found.
Do we need Microsoft 365 E5 to use Copilot properly?
Copilot itself is a separate add-on licence available on top of Business Standard/Premium or E3/E5, not exclusive to E5. That said, E5's more advanced Purview and data governance features make it easier to manage the oversharing risk Copilot introduces, which is worth weighing up alongside the Copilot licence cost itself.
How long does a proper Copilot readiness review take for a small business?
For a typical small business, a focused permissions and sharing review can usually be completed within one to two weeks, depending on how much cleanup is needed once issues are found.
Should we pilot Copilot with a small group first?
Yes, this is generally the sensible approach - piloting with a small, well-understood group of users lets you observe what it actually surfaces and catch any oversharing issues before rolling it out organisation-wide.
We run Copilot readiness reviews for Perth businesses - permissions cleanup, sensitivity labelling, and a staged rollout plan before anyone flips the switch.
Microsoft 365 Services →Considering rolling out Copilot?
Call 0433 087 091 - we'll run a readiness check before you turn it on, no obligation.
Get a Free Copilot Readiness ReviewFor related reading, see our guides to Microsoft Copilot for Perth businesses and auditing external sharing in SharePoint and OneDrive.