TL;DR
- Microsoft’s Copilot blueprint breaks adoption into Pilot → Deploy → Operate, with oversharing mitigation at every step.
- Use SharePoint Advanced Management (SAM) to tighten sharing, expire stale access, and clean up inactive sites before rollout.
- Sensitivity labels and DLP (data loss prevention) can restrict what Copilot can read or summarize; know that container (site/group) labels don’t flow down to files.
- Start with a least-privileged pilot on low-risk sites, aligned to Zero Trust.
Why “permissions first” matters
Copilot surfaces content users already have permission to access. If your M365 has legacy sharing, broken inheritance, or overly broad groups, Copilot can unintentionally expose sensitive material to legitimate users who simply had too much access. Microsoft’s Oversharing Blueprint makes reducing exposure the first order of business.
Step 1 — Reduce oversharing with SharePoint Advanced Management
Use SAM to fix sharing at the org and site levels before any widescale Copilot enablement:
- Set safer defaults (disable “Anyone” links where possible, require expiration, restrict external domains).
- Run Data Access Governance reports to find overshared sites/files and remediate.
- Apply inactive sites policies and site ownership policies to close or reclaim drift.
- Leverage new AI insights in the SharePoint admin center to spot patterns and recommended actions.
Step 2 — Label what matters and control Copilot’s reach
- Use Microsoft Purview sensitivity labels on files and libraries; tie labels to encryption and scoped permissions that block Copilot from extracting content when required.
- Add DLP policies scoped to AI so Copilot can’t summarize “Highly Confidential” items (it can still link out, respecting user access).
- Important nuance: container labels (on Teams/Groups/Sites) don’t automatically apply to items inside; label content where it lives.
Step 3 — Pilot on least-privileged sites
Pick a few low-risk, well-governed sites. Confirm owners, trim legacy sharing, label sensitive libraries, and ensure conditional access/MFA are in place. This aligns with Microsoft’s Zero Trust guidance for Copilot pilots.
Step 4 — Monitor & iterate
Schedule monthly reviews of Data Access Governance reports; automate fixes at scale (PowerShell support is available) and move from Pilot → Deploy → Operate phases as your posture improves.
Quick checklist (copy/paste)
- Org sharing: disable Anyone links; set expiration; restrict external domains.
- Site review: confirm owners; remove broken inheritance; close inactive sites.
- Labels: apply/file-level sensitivity labels to Restricted/Confidential libraries; test protected access.
- DLP for AI: block Copilot summarization of “Highly Confidential.”
- Pilot: least-privileged sites only; MFA/Conditional Access enforced.
- Reporting: run Data Access Governance and remediate monthly; script at scale.
FAQ
Do I need an extra license for these controls?Many readiness features live in SharePoint Advanced Management (SAM), an add-on available to commercial, public sector, education, and more.
Will a Team labeled “Confidential” keep files confidential in Copilot?Not by itself—container labels aren’t inherited by items. Apply labels to the files/libraries directly.
Can labels actually stop Copilot from reading a file?Yes. User-defined sensitivity label permissions can block Copilot from extracting/processing content.
Can I stop Copilot from summarizing highly sensitive content?Yes—use scoped DLP to prevent summarization of labeled items (while still allowing links that respect access).
Sound like too much to do on your own? Want a 2-week “Permissions-First” Copilot Sprint? We’ll trim legacy sharing, apply labels on your top sites, set AI-scoped DLP, and stand up a least-privileged pilot.