File reference DLP checks: When a user tries to reference other files in a prompt – like pulling data or slides from other labeled documents – Copilot checks DLP policies before retrieving the content.
If there is a DLP policy configured to block Copilot processing of files with that file’s sensitivity label, Copilot will show an apology message rather than summarizing that content – so no accidental oversharing occurs.
Enabling DLP for M365 Copilot in Word, Excel, and PowerPoint follows a setup similar to configuring DLP policies for other workloads. From the Purview compliance portal, you can configure the DLP policy for a specific sensitivity label at a file, group, site, and/or user level.
If you have already enabled a DLP for M365 Copilot policy with the ongoing DLP for M65 Copilot Chat preview, no further action is needed – the policy will automatically begin to apply in Word, Excel, and PowerPoint Copilot experiences.
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