Who is this article for?

Users who want to use the desktop app with New Outlook.

Ideagen Mail Manager desktop v15.0 build 2993 or later is required.

This article explains how to prepare your system, install the web add‑in, and enable the latest version of Outlook while continuing to use your usual filing workflows.

1. Prerequisites

Before installing, make sure your PC meets all of the following requirements.

1.1. Operating system

• Windows 10 or Windows 11 (64‑bit only) is supported.
• Windows 8.1 (64‑bit) is untested but should work.
• Server versions of Microsoft Windows 2012 and later are untested but should work.

1.2. Hardware

• An Intel processor running at 2.5 GHz or faster with at least two cores.
• 8 GB RAM or more.
• A minimum screen resolution of 1280 × 768.
• Microsoft .NET Framework 4.8 or newer installed.

1.3. Microsoft Outlook

• A licensed Windows version of Microsoft 365 or Outlook 2019 must be installed. Classic Outlook must be present on the machine.
• New Outlook or Outlook on the web uses a web add‑in. This is not compatible with the existing web add‑in, so remove any previously installed web add‑ins before continuing.
• A working and tested version of Ideagen Mail Manager must be installed.
• Your mailbox must be hosted on Exchange Online.

2. Preparation

Before installation, an MS365 administrator must approve the desktop app’s web add‑in for the organisation’s SharePoint tenant.

You must deploy the web add‑in either to each machine individually or through the MS365 admin centre.

Note: This version works with a single primary mail account only. It is currently available for per‑user deployments. A per‑machine installer is planned.

3. Installing the web add‑in

3.1. Single user

To install the add‑in for one user, follow these steps.

1. Open the manifest file.
2. Right‑click anywhere on the page.
3. Select Save As.
4. Save the file as an .xml file.
5. Follow Microsoft’s instructions for installing custom add‑ins.

Note: If you do not see the option to add a custom add‑in, your administrator must install the web add‑in for you. See the steps for multiple users below.

3.2. Multiple users

The basic steps for organisation‑wide deployment are listed here. These may vary slightly depending on Microsoft updates. You can find the full guidance in Microsoft’s documentation on deploying add‑ins in your organisation.

To deploy the add‑in across multiple machines:

1. Open the manifest file.
2. Right‑click anywhere on the page.
3. Select Save As.
4. Save the file as an .xml file.
5. Go to the Microsoft 365 admin centre.
6. Open Settings.
7. Select Integrated apps.
8. Select Upload custom apps.
9. Select Office Add‑in from the App type dropdown.
10. Upload the manifest file.
11. Choose whether to assign the add‑in to everyone or to specific users or groups.
12. Select Deploy to complete the installation.

4. Enabling the new Outlook version

Once your PC meets the prerequisites and the add‑in has been deployed, you can enable the new version on the user’s machine.

To enable the new version:

1. Open Classic Outlook.
2. If you are not prompted automatically, select Check for updates.
3. Complete any installation or update steps.
4. Close and reopen Classic Outlook.
5. Open User preferences.
6. Go to Microsoft 365.
7. Select Share locations from your PC.

8. Go to Updates.
9. Select Enable Windows desktop support for New Outlook (Preview).

10. Select OK.

The update may take a few minutes. During this time, your existing icons in Classic Outlook will become inactive.

You can then open New Outlook or Outlook on the web on this machine.

Tip: You can opt out at any time by switching back to Classic Outlook.

Further reading

• Using Mail Manager desktop with New Outlook
• Switching back to Classic Outlook
• Release notes