Disable Janusseal App for Outlook in desktop Windows Outlook when Janusseal for Outlook present

Janusseal App for Outlook is an Office web add-in which is designed to provide security classification capabilities in a range of Outlook variants:

  • Outlook on the Web (OOTW; formerly OWA)
  • Outlook on Windows
  • Outlook Mac
  • Outlook Mobile

Janusseal App for Outlook also has a big brother - Janusseal for Outlook - which is an Office COM add-in provides even greater security classification capabilites, but which only operates in:

  • Outlook on Windows

Janusnet has a number of customers who want Janusseal App for Outlook for OOTW, but the big brother, Janusseal for Outlook for Outook on Windows. However, since Janusseal App for Outlook also operates in Outlook on Windows there is a potential for the products to clash and so the customer wants Janusseal App for Outlook to be switched off in Outlook on Windows.

Janusnet have embedded some features in the two products so that Janusseal for Outlook will set an indicator in Outlook that tells Janusseal App for Outlook to de-activate its functionality in Outlook on Windows. While this works, Janusseal App for Outlook's code is still loaded in Outlook on Windows and does perform some minor operations upon every message send event in order for it to realise that it is does not need to show its classification dialog. Many users still notice a notification in the toolbar that "Janusseal App is operating on your request" and it can slow down the send operation.

Fortunately, Microsoft are finally providing a new feature in Outlook on Windows that will allow it to totally disable Janusseal App for Outlook when Janusseal for Outlook is present. This feature can be set in Outlook using two ways:

  1. the installation manifest of Janusseal App for Outlook
  2. a GPO (or registry) setting that Outlook on Windows reads

For the immediate term, Janusnet is recommending customers implement option 2 because it means you do not have to re-install Janusseal App for Outlook to refresh the manifest. 

The remainder of this article details the implementation of option 2.

Article Information
how to
Date created: 
26 Feb, 2021
Last updated: 
23 Nov, 2023 13:48
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At the time of writing, this feature in Outlook on Windows is working for:

  • Beta Channel
  • Current Preview Channel
  • Current Channel
  • Monthly Enterprise
  • Semi Annual


Using a Group Policy Object policy (or Windows registry setting) to define equivalent COM add-in

The new feature in Outlook on Windows is such that if Outlook is told there is a COM add-in that is equivalent to a web add-in, and that COM add-in is installed and operational in Outlook, then Outlook will disable the web add-in.

Hence, we can define a setting which defines that the Janusseal for Outlook COM add-in is equivalent to Janusseal App for Outlook web add-in.

This setting can be implemented in one of two ways:

  1. A Group Policy Object policy setting of Outlook
  2. A registry setting under HKEY_CURRENT_USER

Group Policy Object setting

The relevant GPO policy setting for Outlook is available in version 5140.1000 and above of the Administrative Template file for Microsoft 365, Office 2019 and Office 2016. The download for version 5140.1000 is available here. This procedure assumes you already have a GPO for managing Office configuration, or you are familiar with administering Group Policy Objects.

Using the Administrative Templates, the policy setting is available under the Administrative Templates of the User Configuration tree

  • Microsoft Outlook 2016 / Miscellaneous / Deactivate Outlook web add-ins whose equivalent COM or VSTO add-in is installed

GPO policy setting to deactivate web add-ins


After enabling this policy setting, two values should be added for Janusseal App for Outlook to be disabled when Janusseal for Outlook is present after clicking the Show button:

Value name Value
1e06ce8d-c8b6-48c9-b539-3d5f0328991f janusSEAL.OutlookAddin
8fa4d68a-8ea8-470e-ba41-0b66ba031257 janusSEAL.OutlookAddin

This GPO then needs to be applied to workstations where Outlook is present.

Registry Setting

The following registry file will disable either

  • Janusseal App for Outlook
  • Janusseal App for Outlook (Preview)

if Janusseal for Outlook COM add-in is present and operational

Windows Registry Editor Version 5.00


The first name-value pair indicates that the web add-in with unique identifier 1e06ce8d-c8b6-48c9-b539-3d5f0328991f has an equivalent COM add-in with identifier janusSEAL.OutlookAddin; these are Janusseal App for Outlook and Janusseal for Outlook, respectively.

The second pair is for the Preview install of Janusseal App for Outlook and Janusseal for Outlook; some customers have a second instance of Janusseal App for Outlook installed, and this has a different unique identifier so that it does not clash with the standard version of Janusseal App for Outlook. Janusnet recommends including this second pair even if your organization is not using the Preview mode of Janusseal App for Outlook.

There are some customers with advanced installs of Janusseal App for Outlook where there are multiple instances of the Janusseal App with varying configurations targetting different user groups. If this is the case for your organization you will have to use the Get-App cmdlet in Exchange Management Shell to determine all the unique identifiers (GUIDs) of Janusseal App in use, and add appropriate extra name-value pairs to the registry based on the syntax shown above.

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Applies To
Janusseal App for Outlook