Microsoft Advises IT Admins to Restrict Access to Leaked One Outlook Client

Windows 11

Last week, Microsoft’s web-based One Outlook client (Project Monarch) leaked online, generating some interest among Outlook enthusiasts. The app is based on the Outlook web app for Microsoft 365 commercial customers, and it currently only supports work and school accounts.

If Microsoft had yet to acknowledge the existence of the app, it has now issued an advisory for organizations that would like to prevent employees from using this unreleased version of Outlook for Windows. In a new message spotted by Tero Alhonen on the Microsoft 365 Admin center, Microsoft says that the leaked Outlook app is missing some key features that will be available in the official release, and it encourages users to wait for an upcoming official beta.

“We are aware that some users can access an unsupported early test version of the new Outlook for Windows. This version is missing some of the features and enhancements that will be available later for our customers in the Beta Channel. We encourage our customers to wait for the beta version to be released,” Microsoft explained in a message on the Microsoft 365 Admin Center.

How to block employee access to the new One Outlook client

Microsoft has also outlined some instructions to help IT Admins disable employee access to the leaked One Outlook app. To do so, you will need to follow the step-by-step guide available in this support document which includes PowerShell instructions.

It is important to note that following these instructions will only prevent select or all users from connecting their Microsoft 365 accounts to the leaked One Outlook app, and this won’t stop them from downloading it. The company recommends IT Pros to use the same PowerShell instructions to unblock this new Outlook app for users once the app will be officially available in beta.

Currently, there is no word on when Microsoft plans to make the One Outlook client generally available for Office Insiders. However, the new app should begin rolling out to the Beta Channel sooner rather than later. We may well see Microsoft make an official announcement regarding One Outlook at its Build 2022 conference later this month.