MC844915 - (Update) Microsoft Outlook: Open attachments in desktop apps from the new Outlook for Windows

Updated September 5, 2024: We have updated the rollout timeline below. Thank you for your patience.

In new Outlook for Windows, users will be able to open attachments of all types in their preferred desktop apps by double-clicking on them.

This message is associated with Microsoft 365 Roadmap ID 401123.

When this will happen:

General Availability (Worldwide): We will begin rolling out early September 2024 (previously late August 2024August) and expect to complete by early October 2024 (previously late September 2024.September).

General Availability (GCC): We will begin rolling out early October (previously late SeptemberSeptember) 2024 and expect to complete by mid-late October 2024.2024 (previously mid-October).

How this will affect your organization:

This feature is designed to streamline the process of opening attachments in desktop apps by reducing the number of steps, making it more efficient in your daily workflow.

What's new

Previously, double-clicking on an attachment in new Outlook for Windows would open a preview of the file within Outlook. This meant that if users wanted to open the file in a desktop app, they would first have to save the file locally.

Now, when a user double-clicks on an attachment, the file will open in the desktop app specified as the default app to open that file type in the user's operating system, just like in Outlook Desktop and Windows Mail apps. Single-clicking on an attachment will continue to open a preview of the file within Outlook.

It's important to note that, for security reasons, users will see a confirmation dialog every time they open an attachment of a certain file type unless they choose to dismiss it permanently. To do so, they must uncheck the "Always ask before opening this type of file" checkbox for each file type (.pdf, .docx, .xlsx, jpeg, etc.).

This feature is available by default.

What you need to do to prepare:

This rollout will happen automatically with no admin action required. You may want to notify your users about this change and update any relevant documentation as appropriate.