Microsoft 365 stores every AI prompt and response as a mailbox item. Collecting them is a different job from collecting mail.

Every prompt a custodian types into Microsoft 365 Copilot, and every response it returns, is stored in that custodian’s mailbox. So are their ChatGPT Enterprise sessions, their Microsoft Foundry and Entra app interactions, their Copilot Studio activity, and the AI-generated notes from their Teams meetings. These are mailbox items with their own item classes. They are searchable, holdable and producible — and a default eDiscovery search will not return them.

That gap matters now because the question has stopped being hypothetical. If a custodian used AI to draft a memo, summarise a negotiation, analyse a spreadsheet or decide what to recommend, there is a record of it, and opposing counsel is entitled to ask.

What Copilot eDiscovery collection actually involves

Collection runs through Microsoft Purview eDiscovery using the Item class condition with Copilot activity selected. The scope is wider than most teams expect: separate item classes cover Copilot in Word, Excel, PowerPoint, Outlook, OneNote, Loop, Forms, Whiteboard, SharePoint and Teams, plus WebChat, Copilot Chat, Security Copilot, Copilot in Fabric, and connected third-party AI applications including ChatGPT Enterprise. Teams AI notes and Facilitator notes carry their own class.

Pro-Legal Services collects AI interaction data as part of custodian collection rather than as a follow-up request after someone notices it is missing. We run forensic data collection, ESI processing and defensible production for law firms, corporate legal departments and government agencies across Washington DC, Maryland and Virginia, and Microsoft 365 eDiscovery is a core workflow rather than a side capability.

The parts that go wrong

• Purge operations are capped at ten items per mailbox, so remediation of a large AI population is an iterative process, not a single action.
• Holds and retention policies block deletion. The documented workflow requires removing them, recording what was removed, purging, verifying and reapplying — a sequence that creates real spoliation exposure if it is run out of order or left unfinished.
• Deleting a conversation does not delete the AI’s stored memory of it. Inferred memory persists and has to be addressed separately.
• Several item classes overlap. Teams Chat, Channel and Meeting share a class, and Facilitator shares the broad Teams message class, so an untuned search over-returns and hands the other side a proportionality argument you did not need.
• Copilot items show a non-routable application identity in the From and To fields, which breaks conventional custodian and participant analysis unless the review is configured for it.
• Deleted items sit in a hidden holds folder before permanent removal, and the user is never notified.

Why this is a vendor problem, not an administrator problem

The people currently writing about Copilot item classes are Microsoft 365 administrators writing for other administrators. They are describing a tenant configuration task. What a litigation team needs is different: a preservation scope that names AI interaction data explicitly, a collection that captures it defensibly, a production that identifies it correctly, and a written record of how all three were done. That translation from item class to collection protocol is the work.

We have been doing eDiscovery services, forensic data collection, ESI processing, managed document review, AI document review and defensible production since 1999, on Relativity, RelativityOne and our own Questa platform. AI interaction data is the newest data source we collect. It is not the first one that arrived faster than the guidance did.

Related: Microsoft Purview eDiscovery, Microsoft 365 data collection, Teams data collection, AI document review for litigation, litigation hold services, ESI processing, forensic data collection services, defensible production, legal data management.

Pro-Legal Services, Inc. provides Microsoft 365 eDiscovery and forensic data collection from Arlington, Virginia, serving law firms and corporate legal departments in Washington DC, Maryland and Virginia, and supporting matters in federal and state courts nationwide.

Not sure whether your hold covers AI data? Send us your custodian list and your Microsoft 365 configuration and we will tell you what is in scope and what your current preservation language misses. Pro-Legal Services, Inc. · 1550 Wilson Blvd, Suite 250, Arlington, VA 22209 · 202-955-9400 · info@pro-legal.com