Microsoft 365 Copilot memory: what it keeps about your employees is now a retainable record

What Microsoft announced on August 21

Message RM569612, published on August 21, 2026, announces retention for Microsoft 365 Copilot memory, generally available this month. Purview can now preserve historical versions of memory items for security, compliance and investigation purposes.

To see why this is a change and not just another feature, you need to know where that memory lives. Microsoft stores it in a hidden folder inside each user's Exchange mailbox. It therefore inherits encryption at rest and Customer Lockbox, like the rest of their mail. Until now, though, Microsoft's own documentation was explicit on one point: Purview retention policies did not apply to those items.

Microsoft 365 Copilot memory is on by default, licence or not

Enhanced personalization is turned on by default. No action is required to switch it on, one is required to switch it off. And it reaches further than most teams assume: the feature is available to Copilot Chat users with or without a Microsoft 365 Copilot licence.

What Copilot keeps falls into three buckets: memories the user saves on purpose, details inferred from their chat history, and custom instructions. The first two are discoverable through eDiscovery and Content Search, under the IPM.Contact item class. Custom instructions are not.

Put plainly: Copilot has spent months building a profile of preferences, working style and project context for every one of your users, inside their mailbox, and that profile is discoverable.

Three blind spots retention does not close

Retention settles preservation. It settles nothing else.

• No audit trail. Memory and personalization actions generate no entry in the Purview audit log. You will not know who changed what, or when.
• No content filtering. An administrator cannot restrict what goes into memory. It is all or nothing.
• Deletion does not follow. Deleting a conversation from Purview or eDiscovery does not delete the associated Copilot memory. And purges are capped at ten items per mailbox at a time: this is an incident response tool, not a cleanup tool.

The only admin lever runs through Graph

There is no PowerShell cmdlet and no admin center screen for this control. Enhanced personalization is configured through Microsoft Graph, using the enhancedPersonalizationSetting resource. A tenant administrator has to write a script.

If you turn it off at the tenant level, users see every personalization control greyed out and cannot turn it back on themselves. This is not a setting, it is a governance decision. Make it deliberately, and document it.

What Law 25 requires you to check

Since September 2023, a Quebec business using technology that can identify, locate or profile a person has to inform that person in advance and offer the means to turn those functions on or off. For public bodies, the Act respecting access to documents goes further at section 65.0.1: those functions must be off by default, and the person has to take a positive step to activate them.

Copilot memory, meanwhile, is on by default.

Does Copilot memory qualify as profiling technology under the Act? That is a legal determination and we are not making it here. But it is exactly the question to put to your privacy officer, with the answer in writing. The same exercise applies under the GDPR for your French entities.

Where to start this week

Five moves, in this order.

• Work out who is actually affected. Memory follows Copilot Chat, not just Copilot licences. Pull the list of active users, not the list of licences purchased.
• Decide the on or off question before the retention question. Leave it on, turn it off for everyone, or turn it off for the groups handling sensitive personal information: that is the first call, and it is made at the tenant level.
• Turn on retention now that it exists. Without a policy, a saved memory stays until the user deletes it themselves.
• Update your privacy notice and your AI usage policy. An obligation to inform people in advance does not survive a silent rollout.
• Run an access request end to end. An employee asks what the organization holds about them: how long does extraction take, and who does it?

A preview, with very real data

The documentation still marks the feature as preview, which means it can change. That changes nothing about the urgency: the data is already piling up. Every week without a decision is another week of profiles sitting in mailboxes nobody audits.