# Microsoft 365 Email Archiving – Complete Setup Guide

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**Microsoft 365 Email Archiving – Complete Setup Guide (Knowledgebase Format)**

This guide explains how to enable and configure **Microsoft 365 Email Archiving**, including Online Archive Mailboxes, Auto‑Expanding Archive, and Retention Policies.

** Overview**

Microsoft 365 provides built‑in archiving features that help organizations store older emails securely and reduce mailbox size. Archiving includes:

- **In‑Place Archive (Online Archive Mailbox)**
- **Auto‑Expanding Archive (Unlimited Storage)**
- **Retention Policies** to automatically move old emails
- **Litigation Hold** for compliance and legal protection

This article explains how to enable and configure each feature.

** Prerequisites**

Before enabling archiving, ensure:

- You have **Microsoft 365 Business Premium**, **E3**, **E5**, or **Exchange Online Plan 2**
- You are a **Global Admin** or **Compliance Admin**
- The user mailbox is active and licensed

**1. Enable Archive Mailbox (Online Archive)**

The Online Archive mailbox provides additional storage for older emails.

**Steps**

1. Sign in to **Microsoft 365 Compliance Center** 
https://compliance.microsoft.com
2. Go to **Data Lifecycle Management → Archive**
3. You will see a list of users
4. Select the user you want to enable archiving for
5. Click **Enable Archive**
6. Wait 5–10 minutes for provisioning

**Result**

A new mailbox called **Online Archive – user@domain.com** appears in Outlook and Outlook Web.

**2. Enable Auto‑Expanding Archive (Unlimited Storage)**

Auto‑expanding archive increases archive capacity automatically beyond 100GB.

**Steps**

1. Go to **Compliance Center**
2. Navigate to **Data Lifecycle Management → Archive**
3. Click **Settings**
4. Enable **Auto‑expanding archive**

**Result**

Microsoft automatically adds additional archive space as needed.

**3. Create Retention Policy to Move Old Emails to Archive**

Retention policies automatically move emails older than a specific age (e.g., 1 year) to the archive mailbox.

**Steps**

1. Open **Compliance Center**
2. Go to **Data Lifecycle Management → Microsoft 365 retention**
3. Click **Create retention policy**
4. Enter a name (Example: *Move emails older than 1 year*)
5. Choose **Retention settings**:
6. Choose locations:
7. Assign the policy to:
8. Save and publish the policy

**Result**

Emails older than the defined period automatically move to the archive mailbox.

**4. Enable Litigation Hold (Optional)**

Litigation Hold preserves all mailbox content, including deleted items.

**Steps**

1. Go to **Microsoft 365 Admin Center**
2. Open **Active Users**
3. Select the user
4. Go to **Mail → Manage Litigation Hold**
5. Enable **Litigation Hold**
6. Set a duration (or leave unlimited)
7. Save changes

**Result**

All emails are preserved for legal compliance.

**5. How Users Access the Archive**

**Outlook Desktop**

- Appears as **Online Archive – user@domain.com**

**Outlook Web**

- Appears under folder list as **Archive Mailbox**

Users can drag and drop emails or rely on retention policies.

** 6. Verify Archive Status**

To confirm archiving is enabled:

**Using Compliance Center**

- Go to **Archive**
- Check the **Status** column (Enabled/Disabled)

**Using PowerShell (Optional)**

Get-Mailbox -Identity user@domain.com | Select ArchiveStatus

**7. Common Issues & Solutions**

| **Issue** | **Cause** | **Solution** |
| --- | --- | --- |
| Archive not visible | Outlook not refreshed | Restart Outlook |
| Archive not enabled | License missing | Assign E3/E5/Business Premium |
| Retention not working | Policy not applied | Re‑publish policy & wait 24 hrs |
| Auto‑expanding not growing | Not reached threshold | Wait until archive hits 90GB |

**Conclusion**

Microsoft 365 archiving is a powerful tool for managing mailbox size, ensuring compliance, and storing long‑term email data. By enabling Online Archive, Auto‑Expanding Archive, and Retention Policies, your organization can maintain clean, efficient mailboxes with unlimited storage.