Send S/MIME or Microsoft Purview encrypted emails in Outlook using a work or school account with a qualified Microsoft 365 subscription.

Learn how to use encryption and other security settings to protect messages sent from Outlook.

If you have a Microsoft 365 Family or Microsoft 365 Personal subscription, Outlook includes encryption features that let you share your confidential and personal information while …

Learn how to identify and open encrypted and protected emails no matter what email client you're using.

In an email message, choose Options, select Encrypt and choose the encryption option that has the restrictions you'd like to enforce, such as Do Not Forward or Encrypt-Only.

You can use encryption and digital signatures in new Outlook, classic Outlook, and Outlook on the web for work or school accounts to increase the security of messages.

4 days ago · Enabling cross-tenant access is the simplest workaround as it allows encrypted emails you send to other external tenants to be opened successfully. To do this, follow these …

Jan 6, 2026 · After updating to Current Channel Version 2511 (Build 19426.20218) recipients may not be able to open “Encrypt Only” emails. In the Reading Pane you may get a message "This …

Troubleshoot Office 365 message encryption Have you received an encrypted message you can't open? Are you unable to add permissions to a message you want to send? Select your issue …

To apply IRM protection, S/MIME signature and encryption must be removed from the message. The same applies for IRM-protected messages; users can't sign or encrypt them by using …