Microsoft Office 365 warning while adding external participants.

Hi Elados 

#Show Exchange Org Config MailTips

Get-OrganizationConfig | fl Mailtip*

#Enable Mailtips for External Recipients
Set-OrganizationConfig -MailTipsExternalRecipientsTipsEnabled $true

Regards
Andres

Hi Elados,

I have read your question carefully andI understand that you are looking for a way to display (or send) a warning message to employees when they are creating a new email and adding external participants, before they send the email.

Unfortunately, Microsoft 365 does not provide a native feature to display a warning message before sending an email to external participants.

Microsoft 365 primarily focused on implementing warning messages for incoming emails from external sources.

Here's a general methods to consider for implementing a warning message before sending emails to external participants:

1. Third-Party Add-Ins: Explore third-party add-ins or plugins designed for email security and compliance within Office 365. Some third-party solutions offer the ability to prompt users with a warning message before sending emails to external recipients. You can search for such add-ins in the Microsoft AppSource or contact third-party vendors specializing in email security and compliance.

2. Custom Development: If your organization has specific requirements and you have the development resources, you could consider developing a custom solution. This would typically involve using Office 365 APIs and custom code to create an add-in or extension that adds the desired functionality. This option would require technical expertise and resources for development, testing, and deployment.

3. Security Awareness Training: In addition to technical solutions, consider implementing security awareness training for your employees. Training can help them recognize the importance of being cautious when sending emails to external recipients and double-checking recipient addresses before hitting send.

4. Feedback to Microsoft: Microsoft periodically updates Office 365 with new features and enhancements based on user feedback and evolving security needs. If this is a critical feature for your organization, consider providing feedback to Microsoft through official channels. They may consider adding this capability in future updates.