Copilot in Outlook Litigation Hold Awareness: What It Reads and Skips

Official documentation checked October 14, 2026.

Litigation Hold preserves Exchange mailbox content for compliance purposes. It should not be treated as a switch that excludes a mailbox from Copilot, or as proof that a Copilot summary contains every preserved message. To evaluate a summary, separate the mailbox’s preservation settings from the selected Copilot feature’s access and processing limits.

What Copilot Reads and Skips in a Litigation Hold Mailbox

Exchange can preserve deleted items and earlier versions in the mailbox’s Recoverable Items structure. Its non-IPM subtree is not visible in the ordinary Outlook folder list, although users can recover some deleted items through a separate recovery feature. Microsoft explicitly states that Recoverable Items is indexed by Exchange Search and discoverable through compliance search. See Recoverable Items in Exchange Online.

Preservation and Copilot retrieval serve different purposes. A normal thread summary is not an eDiscovery search of all versions and preserved copies. The documentation reviewed here does not provide a complete, hold-specific Copilot folder inclusion table or promise an exclusion notification for every omitted item. Do not infer completeness from the absence of a warning.

Microsoft’s Outlook Copilot FAQ limits the documented scenarios to the user’s primary Exchange Online mailbox. It lists archive, shared, delegate, and group mailboxes as unsupported for those scenarios, and identifies encryption and protection limitations. The exact feature and client matter. A message being retained under a hold is different from a message being encrypted or restricted by a processing policy.

The newer Copilot Chat in Outlook shared/delegated mailbox guide documents expanded summarization and drafting based on existing mailbox or folder access. This is a separate experience from the FAQ scenarios above. Identify the actual feature and rollout instead of treating primary-mailbox limits as universal.

Steps to Verify What Copilot Reads in a Litigation Hold Mailbox

1. Have the administrator verify preservation separately

An authorized Exchange administrator can inspect the mailbox’s Litigation Hold properties through the documented read-only command below. This reports Litigation Hold; it is not a complete audit of all eDiscovery holds, retention policies, or delay holds. Follow Microsoft’s hold-identification guidance for that broader review.

Get-Mailbox -Identity "user@contoso.com" | Format-List DisplayName, LitigationHoldEnabled, LitigationHoldDate, LitigationHoldOwner, LitigationHoldDuration

Replace the example mailbox with the approved mailbox identity after connecting to Exchange Online PowerShell with appropriate permissions. Microsoft documents this inspection in displaying mailbox information. Do not run a Set-Mailbox command or change the hold for this check.

2. Compare a permitted, visible thread

1. Confirm the account, client, mailbox type, license, and Copilot feature being evaluated.
2. Use a non-sensitive existing thread that you are authorized to access, preferably in a designated test mailbox. Do not manufacture missing content by deleting business messages.
3. Use the thread’s Summarize action where supported. Compare its statements with the messages actually available in the thread.
4. Record the source messages, omissions, and any displayed error. A successful summary establishes only the behavior of that example; it does not certify the mailbox’s legal preservation or Copilot’s access to every held item.

3. Use the preservation workflow for historical evidence

If the question concerns deleted messages, older versions, or case completeness, give it to the authorized records or eDiscovery team. Keep searches, exports, and recovery actions within their approved case workflow. Restoring retained evidence into an ordinary folder is not a required Copilot repair.

If Copilot Still Reads Held Items or Shows Errors

A summary that references a currently accessible message is not, by itself, evidence that a hold failed. Investigate preservation through Exchange and Purview. If the aim is to restrict AI processing, inspect supported access, encryption, or Purview DLP controls separately. Microsoft documents DLP restrictions for Copilot; their applicable locations, licensing, and feature limits must be checked.

An empty or unavailable response also does not identify Litigation Hold as the cause. Check the exact feature’s supported mailbox and protection conditions, then escalate with sanitized error details. There is no verified universal “Mailbox exclusions” repair under Copilot Data sources in the documentation reviewed here. Do not remove a compliance restriction or hold to restore a feature.

Copilot Standard Access vs Copilot Under Litigation Hold: Key Differences

The linked sources support these technical distinctions. This article has not tested a tenant under Litigation Hold and does not certify case completeness or prescribe legal retention decisions. Preserve the configured hold while investigating the actual access or processing issue.