Everyday office basics
What can Microsoft Copilot actually see in your files?
Copilot showed up in your Office apps and now it can find things. Nothing about your access changed the day it arrived. This lesson walks through what Copilot can actually reach across Word, Excel, Outlook, Teams and SharePoint, where your prompts go and who can read them, the difference between the work version and the free consumer one, and the single check in the Share dialog that tells you whether a file is quietly open to your entire company.
Copilot cannot open anything your account could not already open. If it surfaces something you were never meant to see, that is oversharing to report, not a secret to keep digging into.
Last reviewed 2026-08-18 by Grayson Dodson. Free, plain-English guidance for everyday work technology.
Copilot did not open a door. It turned on a light.
Here is the single fact that clears up most of the worry. Microsoft 365 Copilot can only show you things your work account could already open. It runs on the same permissions your name has always had, checked fresh every time you ask a question. Microsoft's own documentation puts it plainly: Copilot only surfaces organizational data you have at least view permissions for. If you could not open a folder yesterday, Copilot cannot open it for you today. What changed is not access, it is effort. Before, finding a stray budget spreadsheet meant knowing it existed, knowing the site name, and scrolling for twenty minutes. Now you type a plain question and the answer surfaces in seconds. So when someone at work says Copilot leaked something, what almost always happened is that a file was shared far more widely than anyone realized, often years earlier, and nobody had a reason to notice until the search got good. The classic case is a SharePoint site or folder shared with the group called Everyone except external users, which really does mean every single employee. Copilot did not break that permission. Copilot found it. That distinction matters, because the fix is a sharing fix, not a Copilot fix.
Where it can actually look, app by app
In Word, Copilot works on the document you have open, and you can point it at another file by choosing Draft with Copilot and then Reference a file, which lists documents in your OneDrive and in SharePoint sites you can already reach. In Excel, it reads the open workbook, and it needs that workbook saved to OneDrive or SharePoint with AutoSave on, in xlsx, xlsm or xlsb format, and it works best when your data is formatted as a table with Ctrl and T. In Outlook it summarizes the thread you have open, drafts replies, and searches your own mailbox, not a colleague's. In Teams, Copilot can run live during a meeting without transcription, but the recap you read afterward is built from the stored transcript, so no transcript means no recap. In the Microsoft 365 Copilot app, which you reach by signing in at microsoft365.com with your work account, the reach is widest: anything in the search index your account can open. One real limit is worth knowing. When a file is encrypted by a Microsoft Purview sensitivity label, Copilot checks the usage rights that label grants you, and if you lack the right to extract content, it will not hand that content back.
Where your prompts go, and what Microsoft does with them
Under a paid Microsoft 365 Copilot license, three things stay inside your organization's tenant, the walled-off part of Microsoft's cloud that belongs to your employer: the prompt you type, the work content Copilot pulls in through Microsoft Graph, and the answer it writes back. Microsoft's Product Terms and its Data Protection Addendum cover that traffic the same way they cover your mailbox, and Microsoft states that prompts, responses, and data accessed through Graph are not used to train its foundation models. Say that carefully, though, because two honest caveats sit right next to it. First, when web search is on, Copilot does not send your prompt to Bing. It generates a short query of a few words and sends that, without your username, domain, or tenant ID, and Bing handles it under different terms than the rest of Microsoft 365. The exact queries appear in the citations under the answer, so you can check them yourself. Still, words left the building, so do not paste a customer list and then ask it to search the web. Second, not being used for training is not the same as nobody at work being able to read it. That is a separate question with a different answer.
What your administrator can and cannot see
Your prompts and Copilot's responses are recorded, and it is worth being precise about how, because two different systems are involved. The unified audit log records that an interaction happened: which user, when, in which app, and references to the files Copilot touched, including the sensitivity labels on them. It does not store what you typed. The words themselves, prompt and response both, sit in a hidden folder in your own Exchange mailbox, and an administrator with the right Microsoft Purview role retrieves them through eDiscovery or Content Search, the same tools used for your work email and Teams chats, for a lawsuit or an HR investigation. Practically speaking, nobody is reading your prompts over coffee. What most admins actually look at is the Copilot usage report, under Reports and then Usage in the Microsoft 365 admin center, which shows enabled users, active users, and activity per app, not text. But the capability exists, it is not hidden, and it is the same capability that has always applied to work systems. What your employer cannot see is a conversation you had with the consumer Copilot on your own personal Microsoft account. That line is easier to cross by accident than you would think.
Three Copilots that look almost identical
They share a name, a logo, and a nearly identical box. Microsoft 365 Copilot, recently renamed Microsoft Copilot, is the paid work one, and it grounds answers in your files, emails, meetings and chats. Copilot Chat comes with a work account at no extra cost and carries the same enterprise data protection, but its chat is grounded in the web, not in your organization's content. You can still hand it work material by pasting, by uploading with the plus button, or by typing a forward slash to pick a file you already have access to. Outlook is the real exception, where Copilot Chat can reach your mail, calendar, meetings and a limited set of files. Since April 15, 2026 the difference is labeled in the product: M365 Copilot Premium means the paid add-on, M365 Copilot Basic means no license but a reduced experience still present in the Office apps, and Copilot Chat Basic means no license and no Copilot chat in Word, Excel, PowerPoint or OneNote. The old Work and Web toggle has moved, so do not use it as your tell. Look instead at the green shield near the top, and at the account in the corner.
The ten-minute check, and what to do if you find something
Open a document you consider sensitive in OneDrive or SharePoint in a browser, select it, click Share, then choose Manage access. If you do not see it in the Share dialog, open the details pane with the information icon and look under Has access. What you get is a list of every sharing link that exists on that file, plus the people and groups with direct access. Read the links first. A link set to Anyone with the link works for people outside your company and needs no sign-in. A link scoped to people in your organization works for every employee. If you see Everyone except external users among the groups, that file is effectively public inside the company, and Copilot will cheerfully find it for whoever asks. Then ask Copilot a question about your team's most sensitive topic and see what comes back. If it hands you something you clearly were not meant to have, a salary sheet, a layoff list, a client contract, stop reading. Do not forward it, do not screenshot it to prove a point, and do not go looking for more. Tell the file owner or your IT or security contact in writing, describing what you found and how. Reporting early is the version where nothing bad happens to you.
Common questions
Can Copilot see files I don't have access to?
No. Microsoft 365 Copilot checks your permissions every time you ask, and Microsoft's documentation says it only surfaces organizational data you have at least view permissions for. It has no special key and no separate copy of the company's files. If an answer includes something that surprises you, that file was already shared more widely than you thought, usually through a link anyone can use or a group like Everyone except external users. That is a sharing problem to report to the file owner or your IT contact. Turning Copilot off would only hide it again without fixing it.
Does Copilot read my emails at work?
It reads your own mailbox, when you ask it to. In Outlook it summarizes the thread you have open, drafts replies, and can answer questions about your inbox and calendar. That holds even without the paid license, because Copilot Chat in Outlook is allowed to reach your mail, calendar, meetings and a limited set of files, which is the one place free Copilot Chat touches work data by default. It is not reading in the background, and it cannot open a colleague's mailbox unless you already have delegate access. Your employer's separate ability to search a work mailbox is unchanged by Copilot.
Can my boss see what I ask Copilot?
Possibly, though not casually, and the mechanics matter. The Microsoft 365 audit log records that you used Copilot, when, in which app, and which files it touched, but not your words. The prompts and responses themselves sit in a hidden folder in your mailbox, and someone with the right Microsoft Purview permissions, normally a compliance or security administrator rather than your manager, retrieves them through eDiscovery or Content Search for an investigation or a legal request. Day to day, leadership sees the Copilot usage report in the Microsoft 365 admin center: license and activity counts, not text. Treat prompts like work email.
Is Microsoft using my company's data to train its AI?
Not for its foundation models. Microsoft states that Microsoft 365 Copilot prompts, responses, and the work data retrieved through Microsoft Graph are not used to train those models, and that the same commitment covers Copilot Chat under enterprise data protection. Two caveats are worth knowing. When web search is on, Copilot sends a short generated query to Bing, stripped of your username, domain and tenant ID, and Bing handles it under different terms. And the consumer Copilot on a personal Microsoft account is a different service, where conversations may be used for model training unless you turn that off in the privacy settings.
How do I check who a file is shared with in SharePoint or OneDrive?
Open the file's location in a browser, select the file, click Share, then choose Manage access. If it is not in the Share dialog, open the details pane with the information icon and look under Has access. Read the sharing links first, because that is where over-broad access usually hides: a link set to Anyone with the link works for people outside your organization and requires no sign-in. Then check the people and groups listed. If you see Everyone except external users, every employee can open it. Change it if the file is yours, and report it to the site owner or IT if it is not.