How to Show Hidden Information of an Email in Outlook

Email messages contain much more information than what is displayed in the message body. Behind every email are hidden details such as internet headers, routing information, sender servers, authentication records, message IDs, MIME content, and other technical data.

Viewing this hidden information can help you troubleshoot delivery issues, verify senders, analyze suspicious emails, investigate spam, and better understand how a message traveled through the internet.

In this guide, you'll learn several ways to show the hidden information of an email in Outlook, including a faster and more convenient method using Kutools for Outlook.

View Internet Headers in Classic Outlook

Method 1 A built-in way to view email headers

Steps

1. Double-click the email to open it in a separate window.
2. Click File > Info > Properties.
   
3. Locate the Internet headers box at the bottom of the Properties window.
4. Review the header information.
   

Limitations

• Only shows the header section.
• The information is displayed in a small text box.
• Difficult to read and analyze long headers.
• Requires several clicks to access.

Method 2: Show Hidden Information of Email with Kutools for Outlook

If you frequently need to inspect email headers and hidden message information, Kutools for Outlook provides a much more convenient solution.

Before using this feature, install Kutools for Outlook and activate the add-in.

Steps

1. Select the email whose hidden information you want to view.
2. Click:
   Kutools > Utilities > Show Hidden Information of Email
   
3. The hidden information will be displayed in the preview window of the selected email for easy viewing and analysis.
   

For users who regularly handle email administration or security investigations, this feature can save significant time.

View Message Source in Outlook on the Web

If you use Outlook on the web, you can view the message source directly.

Steps

1. Open the email.
2. Click the More Actions (···) menu.
3. Select View > View message details or View message source (depending on your version).
   
4. Review the email source information.