Microsoft warns against using leaked beta of unreleased One Outlook app for Windows 11

In recent days the yet-to-be-released successor to Windows 11's Outlook app leaked online. Called One Outlook, this unreleased beta version is known as Project Monarch.

This is not the first we have heard of One Outlook; it was originally scheduled for release last year, but the launch was delayed. But the leak was the first time anyone has been able to try out the app, but Microsoft has issued a warning saying that this is an "unsupported early test version" which is missing features.

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Leaks from Microsoft always generate a great deal of interest, and this has certainly been the case with One Outlook. But while there has been much interest, there has also been disappointment that the app is little more than a PWA.

It is not surprising that Microsoft has spoken out and acknowledged the leak. There is, of course, little that can be done to stem the spread of the app now it is out in the wild, the company can still get the message out that this is an incomplete version that will be improved before it is officially released:

Text of the message that has been sent out by Microsoft has been shared on Twitter:

The tweet not only warns against using the unreleased app, it also includes instructions that administrators can follow to disable access to it:

Some users can access an unsupported early test version of the new Outlook for Windows

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.

We recognize the need for tenants to control access to apps in their organizations, so we are releasing early the instructions to do so. We expect to provide more news in the coming weeks about our Beta release. If you would like to block your users from connecting their Microsoft 365 accounts associated with your organization to this new app, please follow the PowerShell instructions. When the beta is available you will need to unblock them using the same instructions.

These instructions prevent the account from syncing to the new Outlook but do not prevent download.

To enable/disable access for a single user:

1. Run the PowerShell app as an administrator

2. Input: Connect-ExchangeOnline -UserPrincipalName <administrator email>

3. Input: set-CASMailbox <Email being enabled/disabled> - OneWinNativeOutlookEnabled <$true> if enabling or <$false> if disabling

There is no word from Microsoft about when we can expect to see the official launch of One Outlook, but it seems that beta testing is just around the corner.

Image credit: Sundry Photography / Shutterstock