How to Archive Office 365 Mailbox? 4 Best Mailbox Archiving Methods

Archiving Office 365 mailbox refers to the strategic process of relocating historical, inactive, or compliance-bound data (emails, calendars, attachments) from the Exchange Online environment to a secure, long-term storage repository.

Typically, it is exercised for long-term data retention, compliance, and legal discovery. So, if you’re searching for a dependable method to archive Office 365 mailboxes, you must explore this detailed guide. It shares 4 effective methods professionals use to archive Microsoft 365 mailboxes individually and in bulk.

So, stay tuned till the end and know “How to archive Office 365 mailbox?”

Why Do You Need to Archive Office 365 Mailbox?

Archiving Microsoft 365 mailboxes is not just a healthy practice for end-user organizations. But an imperative administrative necessity which is driven by:

• Infrastructure Limits
• Legal Obligations
• Budget Optimization

So, here are the primary reasons why enterprises must archive mailbox data:

#1: Managing Primary Storage Quotas

As you know, a Microsoft 365 license imposes a strict storage quota on the primary mailbox (50GB for standard plans and 100 GB for enterprise plans). And once this hard limit is reached, no new emails can be sent or received.

• Archiving an Office 365 mailbox shifts the historical data to a secondary storage tier. This can offer up to 1.5 TB of space with auto-expanding features.
• Additionally, keeping the primary mailbox lean averts Outlook desktop client performance degradation. And prevents corrupted local OST files.

#2: Ensuring Regulatory Compliance

Preserving corporate communications for specific durations (like 5 to 7 years) is legally mandated for heavily regulated sectors (such as finance, healthcare, and government).

• When Office 365 mailboxes are archived, it ensures that immutable records are kept secure for routine regulatory auditing.
• During legal disputes, centralised archive mailboxes optimise the eDiscovery process. Including targeted data extraction.
• Also, a locked archive safeguards critical historical communications from malicious or accidental deletion by employees.

#3: Optimizing IT Licensing Budgets

Archiving Microsoft 365 mailboxes also provides a highly efficient and economical workaround when an employee leaves the organization. Maintaining the active Microsoft 365 subscription of an ex-employee just to retain their mailbox data doesn’t make any financial sense. It will potentially strain the IT budget.

• So, admins can use the automated retention policies to protect the data before account deletion.
• Furthermore, it immediately frees up the premium commercial license to be reassigned to another employee. This permanently secures the legacy data.

#4: Improving Data Security

Relying extensively on the active inbox for historical data storage is not considered a savvy data security strategy. It leaves the enterprise vulnerable to targeted ransomware, accidental deletions, or synchronisation errors.

Archiving the O365 mailbox creates an isolated repository. This secure storage is distinct from daily mail flow and active threats.
Also, external archiving ensures a definitive air-gapped backup (outside of the Microsoft cloud ecosystem).

4 Best Ways to Archive Office 365 Mailbox

Here are the 4 effective methods professionals use to archive Office 365 mailboxes:

#1: Exchange Admin Center (EAC)

Enabling an “In-Place Archive” via the Exchange Admin Center (EAC) is the most straightforward and standard method to archive Office 365 mailboxes. It allows administrators to manually enable the archive for individual users, an ideal method for one-off administrative requests. It is the primary graphical user interface (GUI) for managing Microsoft 365 mailboxes.

Just ensure that the target user has an active Exchange Online Plan 1 (with an Archiving add-on) or an Exchange Online Plan 2 license before activating it.

Steps to enable In-Place using Exchange Admin Center

Step #1: Access the Exchange Admin Center

• Log in to the Microsoft 365 admin portal (using a Global Administrator or Exchange Administrator role).
• Go to the Exchange Admin Center.

Step #2: Move to Mailboxes

• Expand the Recipients section (in the left-hand navigation menu).
• Click on Mailboxes.

Step #3: Select the Target User

• Locate and select the specific user account to configure.
• A flyout details pane will open on the right side of the screen.

Step #4: Open the “Others” Tab

• Click the Others tab (at the top of the user’s flyout pane).
• Microsoft preserves the archive settings here. This setting is situated next to delegation and mailbox limit configuration.

Step #5: Activate the Archive

• Click the Manage mailbox archive link (under the Mailbox archive section).
• Switch the status toggle to Enabled (or “On”).
• Optional Step: Assign a custom name to the archive.
• Click Save.

Once it’s saved, the secondary mailbox development may take a few minutes for the system. The “Active” status will appear in the mailbox list. However, it can take up to 24 hours for the Managed Folder Assistant to start automatically moving older emails out of the primary mailbox (based on the retention policies).

#2: Exchange Online PowerShell

The Exchange Online PowerShell method is an ideal solution for enterprise environments or tenant admins handling hundreds of accounts. It enables them to execute a PowerShell command to enable archive mailboxes for all users. Simply bypassing the slow, manual clicks of the graphical interface.

Apart from bulk provisioning archives, IT admins use this solution for rapid auditing and automated management of In-Place Archives via the Exchange Online Management module.

Here’s the bulk enable archive mailbox Office 365 PowerShell script:

• First, authenticate the session using the Connect-ExchangeOnline cmdlet.
• Filter the target list to prevent errors on accounts (that already have an active archive). To do so, run the following command:

Get-Mailbox -Filter {ArchiveStatus -Eq "None"} -ResultSize Unlimited | Enable-Mailbox -Archive

PowerShell Script to Check Archive Mailbox Size (Across the Entire Tenant):

• Auditing archiving storage is a critical step to ensure users do not hit their database limits (50 GB or up to 1.5 TB if auto-expanding archiving is enabled). It avoids archive storage issues. To monitor storage consumption, use the following script:

Get-Mailbox -ResultSize Unlimited -Archive | Get-MailboxStatistics -Archive | Select-Object DisplayName, TotalItemSize, ItemCount

• This command fetches the display name. Including the exact storage footprint of the archive and all the items stored. Also, to generate a formatted audit report for management, append | Export-Csv -Path “C:\ArchiveReport.csv” -NoTypeInformation

How do I export an Office 365 online archive to a .pst file?

“PowerShell export archive to PST” is a common search query by admins during onboarding or legal discovery. Historically, you could simply run the PowerShell export archive to .pst command New-MailboxExportRequest to extract historical data.

But in modern Exchange Online, Microsoft has deprecated the native PowerShell. And forced administrators to use the multi-step eDiscovery or Content search GUI in the Purview compliance portal. This process is frustratingly slow and prone to timeout errors during large exports.

To tackle these native limitations and maintain efficiency, IT experts heavily rely on SysTools advanced software. This enterprise-grade utility reliably manages bulk extractions of primary and archive mailboxes directly into PST files.

#3: Messaging Records Management (MRM) Retention Policies

The Messaging Records Management (MRM) retention policy is another effective method to archive Office 365 mailboxes. This native lifecycle engine in Microsoft 365 eliminates the need for users to manually drag and drop emails into their In-Place Archive or execute one-off PowerShell scripts.

Using this, administrators can create “Retention Tags” (such as Default Policy Tags or Personal Tags). These retention tags prompt the system to automatically move items from the primary mailbox to the archive mailbox (once they hit a certain age) in the background. The default policy is typically 2 years.

Steps to Configure and Apply MRM for Archiving:

Step #1: Create a Retention Tag

• Go to the Microsoft Purview portal.
• Click Data lifecycle management >> select Exchange (legacy).
• Under the MRM Retention tags tab >> create a new tag >> name it clearly.
• Select the option to apply it automatically to the complete mailbox (default).
• Set the retention period (exact no. of days) >> configure the retention action to Move item to archive.

Step #2: Build a Retention Policy

• Switch to the MRM Retention policies tab.
• Create a new policy and name it.
• Add the Retention Tag (created in step 1) to this policy. Various Personal Tags can also be added to give users manual options in Outlook.

Step #3: Assign the Policy to Mailboxes

• Return to the Exchange Admin Center >> select Mailboxes.
• Select the target users >> open their mailbox settings.
• Under the Mailbox policies section, apply the newly created MRM Retention Policy.
• To assign the policy to the mailboxes in bulk, run the given PowerShell command:

Set-Mailbox -RetentionPolicy "Standard Employee Archive Policy

Step #4: Force the Managed Folder Assistant (Optional but Recommended)

• The Managed Folder Assistant is the background process that executes MRM rules. By default, it runs on a throttled cycle that may take up to 7 days to process a newly assigned policy.
• However, if you want to apply the MRM policy immediately to a particular mailbox, you can use the following PowerShell command:

Start-ManagedFolderAssistant -Identity <[email protected]>

#4: SysTools Ultimate Solution (Third-Party Archiving Utility)

FAQs (Frequently Asked Questions)

Q.1 How do I access my archive mailbox in Office 365?
To access the archive mailbox in Office 365, find In-Place Archive or Online Archive (labelled with your email address) in the left folder pane of Outlook on the Web or the Outlook desktop app.

Q.2 How to archive folders in Outlook?
Follow the given steps to archive a folder in Outlook:

• Open Microsoft Outlook >> click File (in the top left corner).
• Go to Info >> click Tools >> choose Clean up old items (or Archive).
• Right-click “Archive this folder and all subfolders”.
• Select the target folder (from the list).
• Choose a date (in the Archive items older than the box).
• Click OK. This will move the old items into the archive data file (.pst).

Q.3 How do I automatically move old emails to my Office 365 archive?
By applying a retention policy directly to the folders, you will be able to automatically move old emails to the Office 365 archive. To do so,

• Open Outlook on the Web or the Outlook desktop app.
• Right-click Inbox or any folder (in the left-hand folder list).
• Select Assign Policy (or check under the Policy tab in folder Properties).
• Choose a timeline option (such as 1 year or 5 years to move to archive).
• Repeat the same process for Sent Items or other custom folders.

Q.4 How to recover deleted items from the Office 365 archive?
Apply the simple steps shared below to recover deleted items from the Office 365 archive:

• Launch the Outlook app or Outlook on the Web.
• Scroll down to the “Online Archive” or “In-Place Archive” mailbox.
• Click on the Deleted Items folder (inside the archive).
• Search for the item >> drag it to the archive inbox or use the Move option.