Microsoft Copilot for Microsoft 365 is attractive to law firms because it works inside tools lawyers already use: Outlook, Word, Teams and SharePoint. It can summarize a long email thread, draft a first pass of a letter or find a document by describing it in plain language.
That last capability is where firms get surprised. Copilot generally works within the permissions a user already has. It does not break access rules, but it makes forgotten over-shared content far easier to find. A file that nobody ever stumbled across in a folder tree can show up in seconds when a user asks a natural-language question. Cleaning up permissions before rollout is the most important step.
The core issue: oversharing
Over years, firms accumulate permission shortcuts. A SharePoint site is set to "everyone in the organization" because it was faster. A folder with HR records inherits access from a parent. A link that says "anyone with the link" was sent once and never expired.
Before AI, security through obscurity partly hid these problems. With AI search, obscurity is gone. The risk is not that Copilot is malicious, but that it is efficient at exposing existing mistakes.
Step 1: Decide scope and pilot group
Do not turn it on for everyone at once. Choose a small pilot of perhaps five to ten people across roles, including at least one attorney, one paralegal and one administrator. Limit the first rollout to sites and data you have reviewed.
Step 2: Inventory where sensitive content lives
List the places that hold material with special sensitivity:
- Client matter files and document libraries.
- HR, payroll and partner compensation records.
- Firm financials and trust accounting reports.
- Conflict check data and lateral hire information.
- Anything under a confidentiality order or ethical wall.
Note which of these live in Microsoft 365 and which live in a separate system such as NetDocuments or iManage, because the controls differ.
Step 3: Review permissions at the site and library level
Ask your IT provider for reports showing:
- Sites and files shared with "everyone" or "everyone except external users."
- Anonymous sharing links and their expiration dates.
- Sites with large numbers of members relative to their purpose.
- Guest and external users who still have access.
- Files with broken inheritance, where someone set special permissions that now conflict with the folder.
Remove broad access and replace it with named groups tied to real roles.
Step 4: Apply sensitivity labels and retention
Microsoft's labeling tools let you classify content, such as Confidential or Privileged, and attach protections to it. Labels can restrict access, add encryption and, depending on licensing, limit what AI features can do with the content. Licensing and features change, so confirm what your plan includes with your provider. Even a simple, consistent labeling scheme helps.
Also review retention. Old drafts and abandoned copies increase the amount of material AI can surface. A defensible retention policy reduces that.
Step 5: Check your agreements and settings
Understand how the product treats your data. Ask your provider to confirm, from current documentation, how prompts and responses are handled, where data is processed and what administrative controls exist. Record the answers. ABA Formal Opinion 512 on generative AI stresses understanding how tools handle confidential information, and a written record helps show you did.
Step 6: Train the pilot group
Short, practical training goes a long way.
- AI output is a draft, and a lawyer must review citations, facts and tone.
- Never assume a summary is complete. Check against the source.
- Do not paste material from other clients into a prompt to "match style" unless the firm has approved that use.
- Report anything surprising, such as seeing a file the user should not have access to. That is a permissions finding, not a user error.
Step 7: Monitor and expand gradually
During the pilot, ask IT to review audit logs and gather feedback. If users encounter files they should not, fix the underlying access and document the fix. Expand only when the pilot yields no unresolved exposure.
Questions firms often ask
Does Copilot train on our data? Check current vendor documentation and contract terms, and record the answer in your file.
Can we limit it to certain people? Generally yes, because it is licensed and assigned per user.
Is this worth it? That depends on your workflows. Start with a narrow use, such as meeting summaries or email drafting, and measure the time saved before expanding.
Getting ready with help
A permissions cleanup is useful with or without AI. Counsel Cyber helps firms review Microsoft 365 sharing, configure labeling and plan pilots, so the rollout reveals little you did not already know. If you are considering Copilot, we are happy to assess your readiness.