This article explains how to install the Secure Exchanges add-in in Outlook Web (outlook.office.com) and Outlook New (the new version of the Windows client).
Prerequisites
- Who is it for? Outlook Web or Outlook New users with a Microsoft 365 work or school account.
- What you need: an active M365 account, connected to Exchange Online, on a plan that allows add-ins.
- Three possible paths depending on your role: administrator (situation A), authorized user (situation B), unauthorized user (situation C).
- Duration: approximately 10 to 15 minutes. The add-in may take up to 24 hours to appear after deployment.
Step 1: Determine your situation
The installation depends on your role in Microsoft 365 and on your account permissions. Answer the two questions below, in order, to identify your situation.
Question 1: Do you manage your organization's Microsoft 365 account?
In practical terms, you are the one who adds or removes users, manages licences and receives the invoices from Microsoft.
- Yes: you are in situation A. Go directly to step 2.
- No, or I don't know: go to question 2.
Question 2: Can you install an add-in yourself? (visual test)
- Open Outlook Web or Outlook New.
- Click New message.
- Click the Applications icon (dot grid).
- Click "Get add-ins".
- In the left panel, click "My Add-ins".
- Scroll to the bottom of the page, to the "Custom Addins" section.
- Look at what is displayed:
Step 2: Deploy Secure Exchanges as an administrator (situation A)
Follow this step to deploy Secure Exchanges to all of your users or to a targeted group.
- Open a browser and go to the Microsoft 365 admin centre.
- Log in with your administrator credentials.
- Click "Load custom applications".

- Select "Office Add-in".

- In the "Provide a link to the manifest" field, paste the URL https://office365.secure-exchanges.com/SecureExchanges.xml, then validate.

- Click "Next" and choose who to deploy Secure Exchanges to.

- Click "Next", then "Accept Permissions" to accept the permissions requested by Secure Exchanges.

- Click "Complete deployment".

Note: the add-in may take up to 24 hours to appear in Outlook once the deployment is done.
Step 3: Install Secure Exchanges as a user (situation B)
Follow this step to install Secure Exchanges on your own account. It requires that your account allows the installation of custom add-ins (situation B above).
- In your browser, go to the following address: https://office365.secure-exchanges.com/SecureExchanges.xml
- Right-click on the page, then select "Save As" to download the SecureExchanges.xml file to your computer.

- Open Outlook Web or Outlook New.
- Click "New message" to open the email composition window.
- In the composition window, click the "Applications" icon (dot grid).

- Click "Get add-ins".

- In the left panel, click "My Add-ins", scroll down to the "Custom Addins" section, then click "+ Add a custom add-in".

- Choose "Add from File", then select the SecureExchanges.xml file downloaded in the previous step.

- Confirm the installation when the system prompts you to do so.
Step 4: Activate your licence
- Sign in to Outlook Web or Outlook New.
- Click New message.
- In the message toolbar, click the Applications icon (dot grid).

- In the list of applications, click Secure Exchanges.
- Click "Activate my license".

Your licence is now activated. You can send your first secure email: see the article Send a secure message with Secure Exchanges Outlook Web for the procedure.
Troubleshooting
The Secure Exchanges add-in does not appear after deployment
Possible causes: the 24-hour period has not yet elapsed, or your account is not included in the deployment group. Solution: wait 24 hours. If the add-in still does not appear, contact your administrator so they can check the composition of the deployment group.
Cause: your administrator privileges are insufficient to manage integrated applications. Solution: contact your organization's primary administrator, if your account allows it.
The add-in is visible to only some users
Cause: the deployment was limited to a specific group. Solution: the administrator must check the composition of the deployment group in the Microsoft 365 admin centre.
The "Custom Addins" section is missing or "+ Add a custom add-in" is greyed out
Possible causes:
- Your Microsoft 365 plan does not support add-ins (Business Basic, Exchange Online only, personal account, etc.).
- Your Microsoft 365 administrator has disabled add-in installation by users.
Solution: ask your Microsoft 365 administrator to deploy Secure Exchanges by following step 2.
Need help?
Our team is available to assist you. Write to us at support@secure-exchanges.com
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