When users navigate to the Microsoft 365 My Account portal (under Settings & Privacy) and select the "Delete history" option for their Copilot activity, the system performs a bulk deletion. It removes the user's entire Microsoft 365 Copilot interaction history. Microsoft's privacy controls for this specific portal action do not currently allow for granular deletions, such as filtering by a specific date range, selecting a single conversation, or isolating interactions with a specific agent. Selecting this option clears all saved prompts and responses associated with that user's account.

Microsoft Support Documentation: "Delete your Microsoft 365 Copilot activity history." Section: How to delete your Copilot activity history. (Details the exact steps in the My Account portal and confirms it deletes the entire history).

Microsoft Learn: "Data, Privacy, and Security for Microsoft 365 Copilot" (Article ID: microsoft-365-copilot-privacy). Section: Copilot activity history. (Outlines user data retention and the privacy portal's bulk deletion capabilities).