To main page
RestrictExtRecips for Outlook 2013/2016/2019
E-mail Us
Updated: 9-September-2019
See also: RestrictExtRecips for Exchange 2013/2016


In Exchange online you can use the EAC or Shell to restrict the number of recipients per message for a mailbox.
There is no way to limit the number of external recipients a certain group of people can send to.

If you run Outlook 2013/2016/2019 on Windows, RestrictExtRecips add-in will solve this problem.

Let's suppose an Exchange online administrator has created a distribution list named "RestrictExtRecips_2". Number 2 after underscore means that each member of this list that runs Outlook with RestrictExtRecips add-in installed cannot set more than 2 external recipients in his message.
If a user adds 3 or more external addresses to the "To:" or "CC:" field then the message will not be sent and Outlook will display a warning pop-up window.

The application is a COM add-in for Outlook.

Current version:


  1. As a user with exchange online administrator role log into exchange admin center. Create a distribution list [1] named RestrictExtRecips_2. To the "Notes" place the prefix "Non-restricted:" and the comma-delimited string of internal domains [2]. Example:


    Make sure you are a member of this list [3].

    RestrictExtRecips addin installation Picture 1

  2. On a client workstation where Outlook is installed download archive file and extract all files to C:\Program Files\IvaSoft\RestrictExtRecips directory.
    Exit Outlook in case it is running, run RestrictExtRecips-Demo.msi and follow the instructions.
  3. Start Outlook and click File > Options > Add-ins. Select "COM add-ins" in the Manage: listbox (at the bottom of the page) and click Go button. Make sure that RestrictExtRecips is in the list.

    RestrictExtRecips addin installation Picture 2

    Click Exit button to close the program.



Select Start > Control Panel. Select Programs and features. Select RestrictExtRecips in the list. Right-click and select Uninstall. Follow the instructions.

About this demo version.


Q. Will it help us be more GDPR compliant?
A. Yes. As you know, sharing the email addresses with other recipients is a breach of GDPR regulations - have a look at this article: 5 Ways Your Emails Could Breach GDPR. With RestrictExtRecips you can force users to use "BCC:" instead of "To:" and "CC:".

Q. How can I define the number of external recipients?
A. This number is defined by the name of the distribution list.

Q. What happens if the mailbox is a member of several "RestrictExtRecips_XXX" distribution lists?
A. The lowest number has priority over others.

Q. May I hide "RestrictExtRecips_XXX" distribution list from address lists?

RestrictExtRecips add-in F.A.Q.Picture 1

A. No, don't do that. As soon as you you hide a distribution list, it becomes invisible for RestrictExtRecips add-in.


Licensing policy: the product is licensed on a per-computer (sometimes called per-workstation) basis.

Number of licenses Individual price Your payments will be securely processed by Share-it
€ 35
Shopping Cart
From 10
€ 32
Site license
€ 1800
Shopping Cart
Enterprise license
€ 7000
Shopping Cart
All transactions are securely processed by our external registration providers.

Site license covers a single organization in one location (building complex). If you purchase a site license, you may use the program in an unlimited number of your company's computers within this area.
Enterprise license covers all computers of single organization world-wide. If your company has many branches even with thousands of machines, Enterprise license covers them all.

If you are running Outlook on Windows Terminal Services or Citrix, you should purchase a Site license for each Citrix/TS server.

To main page Microsoft and the Office logo are trademarks or registered trademarks of Microsoft Corporation in the United States and/or other countries E-mail Us