Copilot Does Not Leak. It Reveals.

Most managing partners ask us one question about Microsoft 365 Copilot: is it safe to turn on? A better question is what each person on your staff can open today. That is the whole answer.

What Copilot actually does

Copilot answers each person using only what that person is already allowed to open. It does not give anyone new access. It follows your firm's access settings exactly as they are.

That sounds safe. The catch is how access gets set up in a small firm: usually nobody set it up on purpose. It built up over the years.

Copilot does not create a new leak. It makes an old one easy to find.

Take a partner compensation spreadsheet saved in a shared folder. Eleven people could open it. Nobody ever did, because nobody knew it was there. Being hard to find was doing the job the access settings should have done.

Copilot takes away "hard to find." Someone asks a plain question, and the answer comes back from that spreadsheet. The person was always allowed to open it. They were just never expected to find it.

Nothing broke. That is what makes it hard to explain afterward.

Where the extra access came from

In firms of ten to twenty-five people, four habits cause almost all of it. None of them is anyone being careless.

The move to the cloud. Someone moved the old file server into SharePoint or OneDrive over a weekend. The folders came across as they were. The restrictions often did not, because keeping them was nobody's job.

"Anyone with the link" sharing. If this default was never tightened, every link shared in the last four years still works for whoever has it, and nobody has a list of them.

Whole-folder access. Someone needed one document, so they were given the whole folder. Then the folder kept growing.

Too many administrators. Not everyone on staff holds administrator rights. But everyone who was ever senior, ever set up a laptop, or ever fixed something on a Sunday in filing season does.

Give Copilot licenses to a firm like that and something will come up. The only questions are what comes up first, and who is in the room when it does.

Five checks before you turn it on

This is a review, not a project. For a firm your size it takes days, not months, and you do not need to buy anything.

1. Match access to who works here now. Check who can open what against this week's staff list, not the org chart. People who have left are the usual find: their accounts were kept for handover and never lost any access.

2. Find the "anyone with the link" shares. Set an expiry date on each one, or remove it. Then change the default so the next four years do not repeat the last four.

3. Lock down the files that should never be open to everyone. Payroll and pay. Partner and firm finances. Anything under its own confidentiality agreement. HR matters. In most firms these sit in the same place as everything else, separated only by a folder name.

4. Limit administrator rights to the people who need them. Some people hold admin rights their job does not need. Taking them back is unpopular. It is also the one thing an insurer and an examiner both ask about, in different words.

5. Decide what Copilot is allowed to read. A general assistant that can search everything a person can open is a different risk from a focused one that reads a single document library, one shared set of files. Make that choice when you set Copilot up. It is much harder to change once staff have built habits around it.

Do the first four before anyone gets a license. The review is uncomfortable to run once staff are already using Copilot and finding things.

Which Copilot your staff are using

Several products are called Copilot, and they do not come with the same promises.

The business version is Microsoft 365 Copilot on a commercial license in your firm's Microsoft 365. It comes with Microsoft's enterprise data protection commitments: contract terms set out in the Microsoft Data Protection Addendum and the Product Terms. The consumer versions do not. Microsoft Copilot on a personal account is the free one. Microsoft no longer sells Copilot Pro, and points its subscribers to Microsoft 365 Premium.

They look almost the same on screen. For a firm holding client tax returns, the contract behind them is very different.

So your staff could be "using Copilot" in three places at once, under three different sets of terms, with no record of which is which. Start with a list of which Copilot each person uses. It usually takes an afternoon.

Write the review down

This is the part that matters most later.

Fixing the access is the easy half. The half that pays off is keeping a record: what you checked, on what date, which role did it, what you found, and what you changed. Do the same for the list of Copilot versions and for the decision about what Copilot may read.

For a firm holding customer information, two things here are part of the FTC Safeguards Rule, at 16 CFR 314.4(c). One is controlling who can get to that information. The other is reviewing that access from time to time. In June 2026 the IRS Office of Professional Responsibility asked firms to document their AI procedures. Correct settings alone cannot show either one: that access is controlled and reviewed, or that AI procedures are documented. Correct settings with a dated record of the last review can.

Turn Copilot on after the review, not before, and write the review down while you do it. In that order it costs a few days, once. The other way round it costs the same days later, with people watching.

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