Install an Outlook add-in to view the Microsoft 365 End-User Quarantine

This article explains how to install an Outlook add-in called View Quarantine that will open the Microsoft 365 end-user quarantine in a browser with a single click. This makes it really easy to access the quarantine directly from Outlook. And since this is a true Office add-in, it also displays and works in Outlook mobile and Outlook on the web!

I'm happy to announce that the add-in now also works with Microsoft Government Community Clouds (GCC and GCC High)! View the change log for status and feature updates.

The add-in shows in the Outlook ribbon when viewing any folder that contains mail items.

The View Quarantine add-in for Outlook

Simply click the button to open the Microsoft Defender Online end-user quarantine in your default browser. You may need to sign-in to view the quarantine.

The Microsoft 365 end-user quarantine

I originally built this add-in using the Build your first Outlook add-in - Office Add-ins documentation. This gave me a good head start to build and customize the add-in.

The add-in consists of three files plus icons in various sizes for the different platforms.

Source File	Description
commands.html	An HTML "wrapper" that calls the JavaScript used by the add-in when the button is clicked.
commands.js	The JavaScript functions that provide status and open the end-user quarantine in a browser.
manifest.xml	The real heart of the add-in. It defines the unique ID for the add-in and describes when to display the View Quarantine button and how the add-in functions.
assets folder	Contains six icon files of different sizes and opacity for Outlook, OWA, and Outlook mobile.

I'm currently in the process of publishing this add-in to the AppSource marketplace via the Microsoft Partner Center. Please see the change log. In the meantime, there are two ways you can install the View Quarantine add-in now.

Option 1 -- Install via the Web

You can install the add-in from my website until Microsoft publishes it on AppSource.

Open Outlook and click the Get-Add-ins button in the ribbon. Alternatively, click File and click the Manage Add-Ins button at the bottom.
Click My add-ins in the top left.
Click the + Add a custom add-in dropdown at the bottom of the window under Custom add-ins, then select Add from URL...
Enter the following URL: https://www.expta.com/quarantine/manifest.xml and click OK.

If your mailbox is in a GCC tenant use the following URL: https://www.expta.com/quarantine-gcc/manifest.xml
If your mailbox is in a GCC High tenant use the following URL: https://www.expta.com/quarantine-gcch/manifest.xml

You will see a warning before installation. Click Install to install the add-in.

The add-in will now be listed under Custom add-ins. Note: To remove the View Quarantine add-in at any time, click the ellipses (...) and select Remove.

Close the Add-ins window to add it to the Outlook ribbon.

Option 2 -- Install from Source Files

You can also install the add-in using the manifest.xml file in my source files.

Download the correct source files from my website:

View Quarantine for most world-wide tenants
View GCC Quarantine if your tenant is GCC
View GCC-High Quarantine if your tenant is GCC High

Extract the ZIP file to a local drive or network share.

Open Outlook and click the Get-Add-ins button in the ribbon (shown above).
Click My add-ins in the top left.
Click the + Add a custom add-in dropdown at the bottom of the window under Custom add-ins, then select Add from file...
Browse to the manifest.xml file and click Open.
You will see a warning before installation. Click Install to install the add-in.

The add-in will now be listed under Custom add-ins.

Close the Add-ins window to add it to the Outlook ribbon.

Deploying to All Users in the Organization

Once you're satisfied that the add-in is installed and working properly, you can deploy it to all users in your organization. Here's how to do that:

Open the Microsoft Admin Center and navigate to Settings > Integrated Apps > Add-Ins.
Click Deploy Add-In and Next.
Click the Upload Custom Apps button.
Select I have a URL for the manifest file and enter one of the following URLs:

For standard M365 use https://www.expta.com/quarantine/manifest.xml
For GCC use https://www.expta.com/quarantine-gcc/manifest.xml
For GCC High use https://www.expta.com/quarantine-gcch/manifest.xml

Select whether to install the add-in for everyone or specific users.
Select a Deployment Method.

Fixed (Default). The add-in will be automatically deployed to the assigned users and they will not be able to remove it from their ribbon.
Available. Users may install this add-in by clicking the Get More add-ins button on the home ribbon in Outlook and going to Admin-managed.
Optional. The add-in will be automatically deployed to the assigned users but they can choose to remove it from their ribbon.