Official documentation checked October 14, 2026.
There is no single Copilot conversation-retention period. The answer depends on the account, the service, and whether you mean visible chat history, retained interaction content, or audit records. Do not use a table of “24 hours, 90 days, and 30 days” to make a business deletion or preservation decision.
1. Identify the account and the record you need
First confirm whether the conversation used a personal Microsoft account or a work or school account. A paid consumer plan does not turn a personal conversation into a tenant-managed Microsoft 365 record. Old product names such as “commercial data protection” are not sufficient to identify today’s service behavior.
Record the exact experience, account, date range, and purpose of the question. For example, “How long can I reopen this chat?” is different from “Can our investigator still retrieve the prompt after the user deletes it?” The latter requires the organization’s applicable policies and compliance tools, not just the chat sidebar.
2. Personal Copilot history has its own controls
Microsoft’s current consumer conversation-history guidance says signed-in Copilot retains the last 18 months of interactions in conversation history. This is not a 90-day rule tied to Copilot Pro, and it is not the retention schedule for your work tenant.
On copilot.com, open the history sidebar, use the menu beside the conversation, and select Delete. To request deletion of all personal-account history, use the Microsoft account privacy dashboard’s Copilot app activity section. Check the account carefully before choosing an all-history action. Treat this as the documented history-management process, not a promise that every possible service record or exported copy disappears instantly.
3. Work-account history and compliance retention differ
For work or school accounts, Microsoft’s activity-history deletion process starts in My Account → Data and Privacy → Data options → Copilot activity history. The user selects the Copilot option and submits a deletion request. Processing takes time; content already saved into a document is not removed.
For compliance, interaction content is stored in hidden mailbox storage and managed using the applicable Copilot retention configuration. It is not an ordinary Conversation History folder that an administrator should label as if it were email. There is no universal 30-day conversation expiry established by the documentation. Ask the compliance team which retain, delete, or retain-then-delete rules and holds cover the user.
Microsoft’s Copilot retention explanation describes background processing and the hidden SubstrateHolds stage. The chat interface is not proof of permanent deletion. An applicable retention requirement, litigation hold, delay hold, or eDiscovery hold can prevent permanent deletion even after the user removes history.
4. Review the actual policy rather than inventing a folder rule
An authorized administrator should open Microsoft Purview → Solutions → Data Lifecycle Management → Policies → Retention policies. For a new policy, review the Microsoft Copilot experiences location, applicable Copilot service, user scope, action, and period. The choice must follow the approved records schedule; do not assume all users or all AI services should be included.
Microsoft’s policy-creation guidance also explains the older combined Teams chats and Copilot interactions location. Existing combined policies remain supported, although tenants with separate locations cannot edit them in the same way. Do not delete an existing policy simply because its name looks old.
Policy distribution can take up to seven days, followed by the relevant content-processing stages. Check distribution status and investigate errors. A one-day delete rule is not a guaranteed next-day permanent purge, and there is no general 365-day maximum for all Copilot retention requirements.
5. Keep auditing separate and verify the right outcome
Copilot interactions can generate Purview audit events such as CopilotInteraction. These record activity metadata, including relevant identifiers and resource information; they are not the same as a full prompt-and-response transcript. A usage dashboard is not an auditing switch. See Microsoft’s Copilot audit schema.
For an investigation, use the appropriate authorized eDiscovery process for conversation content and Audit for activity records. Preserve each according to its own policy. Before reporting an outcome, document the account type, selected data category, policy or deletion request, verified scope, date, and remaining exceptions. Avoid copying sensitive conversations into personal documents merely to work around a retention limit.