4.5. Copilot Memory and Instructions
💡 First Principle: Personalization works like a good assistant's notebook about you: some things you told them directly, some they picked up by working with you, and some are standing rules you gave them. Copilot memory has the same three parts. Because each part is stored and removed differently, deleting one thing doesn't automatically delete the others.
Without memory, every chat starts cold and you re-explain your role, your projects and your preferences each time. With memory, Copilot can tailor responses from the start. Copilot personalization and memory are officially in preview and subject to change, although they're widely available, to Copilot Chat users both with and without a license.
The three parts of Copilot memory:
| Part | Where it comes from | Example |
|---|---|---|
| Saved memories | Things you explicitly ask Copilot to remember ("Copilot, remember that…"). A Memory updated confirmation appears | "Remember that I lead Project Atlas, a CRM migration" |
| Details from chat history | Details Copilot infers from your past chats | Copilot notices you usually ask for bullet-point answers |
| Custom instructions | Standing directions you write in settings | "Always put a one-line summary first" |
Managing memory:
- Manage saved memories at Settings > Chat settings > Personalization > Manage saved memories, where you can delete one memory or Delete all.
- Saved memories persist until you delete them.
- Deleting a chat doesn't delete memories created from it. If every chat a chat-history detail came from is deleted, its traces are removed within 7 days.
- Turning off saved memories stops them being used but doesn't delete them. The Chat history setting works differently: if you turn it off, the inferred details are deleted after 30 days, and turning it back on within 30 days restores them.
- A temporary chat doesn't access or store personalized information, but it is still discoverable by admins in Microsoft Purview.
Where memory lives and what admins control: Memories are stored in a hidden folder in your Exchange mailbox, protected by the same mailbox security. The admin control is Enhanced personalization, which is on by default. When an admin turns it off, custom instructions, saved memories and chat history appear turned off in your Personalization settings and you can't turn them back on. Microsoft also notes that Purview retention policies don't apply to memory and memory actions don't create audit log entries, though eDiscovery can find saved and inferred memories.
Not all instructions are the same instructions. Your Copilot Chat custom instructions apply to Copilot Chat. Cowork has its own separate custom instructions (Customize > Preferences, 6.4.2), and a notebook can carry its own instructions too (5.2). Changing one doesn't change the others.
⚠️ Exam Trap: Three "delete" assumptions are all wrong: deleting a chat doesn't delete the memories it produced, turning memory off doesn't erase what's stored, and turning off Work IQ doesn't turn off personalization (2.2.3). To remove a saved memory, delete it in Manage saved memories. To avoid personalization for one sensitive chat, use a temporary chat.
Reflection Question: A consultant asked Copilot to remember a client's name during a project. The project has ended, so she deletes all the chats about it, but Copilot still mentions the client. Why, and what should she do?
