M365 Copilot — Memory & Personalization

At a glance

What it does
Saves what Copilot learns from your conversations — preferences, working style, topics you return to — and uses this to personalise responses across all future sessions.

Where it's stored
Memories are stored in your Exchange mailbox in a hidden folder. They are discoverable by IT admins via Microsoft Purview eDiscovery.

On by default
Memory is enabled for all Copilot licence holders. Admins can disable it at tenant or user level.

You stay in control
View, edit, and delete individual memories at any time. Turn off saving entirely without losing existing memories.

Use case	Who benefits	Signal
Repeated project briefings	PM · Programme Manager	Copilot stops re-asking your project context
Writing style consistency	Communications · Marketing	Responses match your preferred tone without re-prompting
Role-specific defaults	Any Copilot user	"As a finance analyst I need..." no longer needs to precede every prompt
Cross-session continuity	Daily Copilot users	Context from Monday's session informs Tuesday's response

What it is — and when it's worth using

How Memory works

When you chat with Copilot, it looks for information worth remembering — preferences you state, recurring topics, working patterns. If it finds something, it asks you to confirm before saving. You can also tell Copilot directly to remember something ("Remember that I prefer concise bullet-point summaries"). Memories become part of the context for every future conversation, without you needing to re-explain.

Three types of memory

Saved memories — explicit facts you or Copilot saved. Visible and editable in Settings.
Chat history inferences — patterns Copilot learns from your conversation history. Used to personalise responses but not shown as named items.
Custom instructions — standing instructions you set (e.g. "always respond in French", "I work in UTC+1"). Stored and applied to every session.

Less useful for

Users in roles with strict data sensitivity requirements where cross-session context creates compliance risk
Shared device users (memories are per-user, but be aware of who accesses your session)

Setup — 4 steps

Deleting a chat does NOT delete memories

If Copilot saved a memory during a conversation and you later delete that chat, the memory is not automatically removed. Go to Settings → Personalization → Manage saved memories to delete specific items. Chat history details are typically removed within a few days of deleting the associated chats — but Saved memories persist until explicitly deleted.

Open Copilot settings

Go to m365.cloud.microsoft/chat or open Copilot in any Microsoft 365 app. Select the … menu in the upper right corner → Settings.

Go to Personalization

In Settings, select Personalization. You will see three controls: Custom instructions, Saved memories, and Chat history. Each has its own toggle.

Review your saved memories

Under Saved memories, select Manage saved memories. This shows everything Copilot has explicitly saved. You can delete individual items or all at once.

Tell Copilot what to remember

In any Copilot Chat conversation, type: "Remember that [fact]." Copilot confirms the save. You can also say "Forget that I [fact]" to remove a specific memory.

What Memory can and cannot use

Copilot Memory draws only from what you have explicitly told it or what it has inferred from your Copilot Chat conversations. It does not read your emails, files, or calendar to build your memory profile — those are accessed per-query in Work mode, not stored in Memory.

Saved memories — facts you confirmed or asked Copilot to remember

Outlook emails and sent items

Custom instructions — standing preferences you set

SharePoint / OneDrive files

Chat history patterns — tone, topics, recurring contexts inferred from conversations

Calendar events and meeting content

Voice chat context (Jan 2026) — voice sessions can reference saved memories

Teams messages and channels

Information from other users' sessions

Rules for getting the most from Memory

01
Check your memories after the first two weeks. The initial batch of inferences is often broad. Review Settings → Personalization → Saved memories and delete anything inaccurate before it shapes future responses.
02
Use explicit instructions for repeating preferences. Don't rely on inference. If you always want responses in bullet points, tell Copilot directly: "Remember that I prefer bullet-point summaries under 150 words."
03
Use Temporary Chat for sensitive conversations. If you are working on a confidential matter, start a Temporary Chat. It does not access or update Memory, and does not appear in chat history. Access via the chat interface.
04
Turning off Memory does not delete existing memories. Toggling Saved memories to Off stops new saving but preserves what is already stored. To delete existing memories, use Manage saved memories.
05
Memory is per-user, not per-device. Memories follow your Microsoft 365 account across all platforms — desktop, mobile, web. They are stored in your Exchange mailbox, not on the device.
06
IT admins can see your memories via eDiscovery. Memory data is stored in Exchange and is discoverable through Microsoft Purview. Treat saved memories as organisational data, not private notes.

Failure modes to expect

Memory controls are greyed out. Your admin has disabled Enhanced personalization at the tenant or user level. You cannot turn on Memory yourself — contact your IT admin. If the admin has disabled it, all chat history details are removed after 30 days.

Copilot is not using what I told it to remember. Check Settings → Personalization → Saved memories to confirm the item was actually saved. If it is there but Copilot ignores it, try rephrasing the memory as a specific instruction: "Always refer to me as a senior project manager when providing guidance" rather than a vague preference.

I deleted a chat but Copilot still references that context. Chat deletion removes the conversation, not the memories inferred from it. The memory persists in Saved memories. To remove it: Settings → Personalization → Manage saved memories → delete the specific item.