Microsoft 365 Copilot now personalises from work emails and chats, on by default

By Jason Sibley

What happened

On 8 October Microsoft published Message Center notice MC1492154, tagged "New feature". It says Copilot "now uses inferences [from] Microsoft 365 data as context to provide more personalized responses to your work." In plain terms, Microsoft 365 Copilot is starting to learn from what is in staff emails and Teams chats, and from meeting transcripts too. It uses these "work insights" to tailor its answers.

It is on by default. Microsoft says the worldwide rollout began in early October 2026 and should finish by late October, across web, desktop, Mac, iOS and Android. The notice says "No additional work is required from the admin" and "No compliance considerations identified. Review as appropriate for your organization."

Work insights only appear when someone is signed in with a work or school account, and they depend on which Copilot plan your organisation has. Don't assume every account in your business is affected.

Microsoft's documentation says this information is not shared with other users. The memories sit in a hidden folder in the user's Exchange mailbox and follow the same security and compliance policies as other mailbox data.

Sources: MC1492154 (Message Center, reproduced), Manage Copilot personalization and memory, Personalize what Microsoft Copilot remembers, Microsoft Copilot enhanced personalization control

What it means for a small business

For many owners this will make Copilot more useful, because it can get to know your clients and projects without being told each time. So this is a choice to make on purpose, this week.

It is still worth a pause, because many small firms keep customer, staff and supplier personal data in Outlook and Teams. Under UK GDPR (and GDPR in Ireland) the business remains responsible for that data. Is your privacy notice or staff policy clear that Copilot can personalise from work content? Check with your adviser on what it should say.

Microsoft Learn also lists some gaps. Purview retention policies and labels do not apply to Copilot memory, so a "delete after three months" policy for Copilot Chat does not delete memories. There are no admin controls to enforce retention for memory specifically, and admins cannot restrict what type of information is added. Memory and personalisation actions do not create audit log entries in Purview.

Then there are subject access requests. Admins can use Purview eDiscovery or Content Search, and Microsoft Graph Explorer, to search, export and delete a person's memory data (saved and inferred memories). Custom instructions cannot be found that way. Who in your business could do this?

As for controls, each user can switch the toggle off in Copilot Settings > Personalization. On a work account it may be labelled "Chat history & work insights". Switching it off deletes the memories Copilot made, but if it goes back on within 30 days, Copilot adds them back. Admins can turn enhanced personalisation off for the whole organisation or a group through Microsoft Graph. That also switches off saved memories, custom instructions and chat history personalisation for those users, and they cannot turn them back on.

What you can do this week

1. Ask Copilot "What do you know about me" on your own account. You will see a summary, including work insights, and you can ask it to forget a detail.
2. Decide, person by person or role by role, whether the toggle should be on. People who handle HR, payroll or client files are the obvious ones to think about first.
3. Ask whoever runs your Microsoft 365 (your IT provider, usually) whether the enhanced personalisation control should be off for a group. It is set through Microsoft Graph, so it is not a job for a tick box.
4. Use temporary chat in Copilot Chat for sensitive topics. Microsoft says it does not use or update memory.
5. Add a line to your data records or privacy notice saying Copilot memory exists, where it sits, and how you would find it for a subject access request. Check with your adviser on the wording.

How we can help

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