# How to Encrypt Email in Outlook (Microsoft Preview using Microsoft 365 Business Premium)

This article explains how to encrypt emails using **Microsoft Purview Message Encryption (OME)** in Outlook, available with **Microsoft 365 Business Premium**. Encryption protects message contents and attachments so only intended recipients can read them.

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## When to use email encryption

Use encryption when sending:

- Sensitive customer/student/patient data
- Financial info (invoices, bank details)
- Credentials or access details (temporary passwords, links to restricted systems)
- HR/employee information
- Any message that should not be forwarded or read by unintended people

**What encryption does:** encrypts the message in transit and at rest and enforces the protection policy applied (for example, “Encrypt” or “Do Not Forward,” depending on what your organization allows).

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## Before you start (important notes)

- You must be signed in with your **work account** that has **Microsoft 365 Business Premium or Higher License** and your organization must have **encryption enabled**.
- Recipients **outside your organization** can still read encrypted messages. They may be asked to verify their identity (for example, via a one-time passcode) depending on settings.
- Encryption is different from **S/MIME**. This guide is for the built-in **Encrypt** option in Outlook tied to Microsoft 365.

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# Outlook Desktop (Classic) — Windows/Mac

> These steps cover **Outlook Classic** using the **Encrypt** option while composing an email.

### Encrypt a single email

1. Open **Outlook (Classic)**.
2. Select **New Email**.
3. Compose your message and add recipients/subject/attachments.
4. In the message window, go to the **Options** tab.
5. Select **Encrypt**.
    
    [![image.png](https://docs.precision-computer.com/uploads/images/gallery/2026-01/scaled-1680-/THrOiZAlDS12H9sq-image.png)](https://docs.precision-computer.com/uploads/images/gallery/2026-01/THrOiZAlDS12H9sq-image.png)
6. Choose **Encrypt** (or other options you see, such as **Do Not Forward**, if available).
7. Click **Send**.

### What you should see

- After selecting Encrypt, Outlook usually displays an indicator (like “Encrypt” being highlighted) or the chosen protection in the message window.

### If you don’t see “Encrypt” on the Options tab

Try:

- Make sure you are in the **full message compose window** (not a simplified reading pane compose).
- Confirm you’re signed into the correct **work account**.
- Update Outlook (File → Office Account → Update Options).
- If it’s still missing, contact IT, your tenant policies may hide or restrict it.

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# Outlook on the Web (OWA)

### Encrypt a single email

1. Go to **Outlook on the web** (open mail in your browser).
2. Click **New mail**.
3. Compose your message.
4. In the compose window, click **Options** (or the **… More options** menu depending on your layout).
5. Select **Encrypt**.
    
    [![image.png](https://docs.precision-computer.com/uploads/images/gallery/2026-01/scaled-1680-/zzJsLWaf6wkbksAt-image.png)](https://docs.precision-computer.com/uploads/images/gallery/2026-01/zzJsLWaf6wkbksAt-image.png)
6. Click **Send**.

### Tip

If your organization offers multiple protection choices, you may see options like:

- **Encrypt**
- **Do Not Forward**
- Other labeled protections (custom policies)

Pick the one that matches your need.

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## What recipients experience (internal vs. external)

### Internal recipients (same organization)

- Often see the message normally in Outlook, with an encryption/protection banner.

### External recipients (outside organization)

They may:

- Read the message directly in their email client (in some cases), **or**
- Receive a message with a button/link like **“Read the message”** and then:
    
    
    - Sign in with a Microsoft/Google account, or
    - Use a **one-time passcode** sent to their email (depends on your org’s encryption settings)

**Attachments:** protected as part of the encrypted message experience.

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## Best practices

- **Encrypt before you send.** Adding encryption after sending isn’t reliable.
- Keep subjects non-sensitive. Some encryption methods protect the message body and attachments but **subjects may still be visible**.
- Use the minimum necessary protection. If “Do Not Forward” is available and appropriate, consider it when you want to prevent sharing.

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## Troubleshooting checklist

If encryption isn’t working as expected:

1. **Confirm license & account**
    
    
    - You must be using the correct work mailbox licensed for Business Premium.
2. **Confirm you’re using Outlook Classic / OWA**
    
    
    - Some older builds may not show the option.
3. **Check policy availability**
    
    
    - If the Encrypt button is missing, your org may have disabled it or limited it to certain groups.
4. **Try another client**
    
    
    - If mobile is missing the option, test on **Outlook on the web** or **Desktop**.
5. **Escalate to IT**  
    Provide:
    
    
    - Screenshot of the compose window (Options tab or “…” menu)
    - Your Outlook version (Desktop: File → Office Account)
    - Recipient domain (internal/external)
    - Any error text