Classic Outlook Adds Copilot ‘Explain This’ for Selected Email Text

Microsoft’s May 15 Message Center notice, preserved by the M365 Archive, said public preview had begun in early May and general availability was expected to roll out during June. Windows Latest’s August 8 report instead said Microsoft expected the rollout to finish by the end of September. Because those public records disagree, the available evidence does not establish that every eligible tenant already has the feature.

The archived notice says the capability is built into classic Outlook, does not require a separate add-in, and is on by default for eligible users. It also says existing Microsoft 365 security, compliance, and data-protection policies continue to apply. Windows Latest reported that the feature depends on a Microsoft 365 Copilot subscription and that availability may be controlled through Outlook’s Copilot settings.

For administrators, the practical questions are entitlement, update channel, tenant rollout state, and policy configuration. A missing control does not necessarily indicate a broken client when staged service delivery and licensing can both affect availability.

For users, “Explain This” is a convenience layer over selected email content, not an authoritative interpretation. Explanations can still omit context or make errors, so operational, legal, security, or financial instructions should be checked against the original message and trusted documentation. The most defensible conclusion from the retrieved evidence is narrow: Microsoft has documented the feature and current reporting has observed it, but the public rollout timeline remains unsettled.