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Summary: Microsoft 365 Business and Enterprise plans support large email mailboxes and offer Office 365 mailbox export to PST for secure backups. Extended email retention is crucial for compliance, risk management, and productivity. Retention policies in Office 365 handle data preservation and deletion effectively, ensuring secure data management and access when needed.

Microsoft 365 Business and Enterprise plans provide robust storage and security for large email mailboxes. Additionally, you can securely export Office 365 mailboxes to PST for essential backups. Retaining emails becomes imperative due to compliance requirements, preservation of valuable information, and adherence to industry standards. Here are key reasons organizations maintain emails for extended periods.

  • To follow compliances, regulations, and business policies.
  • To minimize the risk related to the old data and its maintenance. Also, for deleting the older and unrequired data.
  • To assist the organization’s employees in allowing them to work on the latest content which is entirely relevant to their job.

At first glance, the term ‘retention’ might suggest data preservation. However, organizations often accumulate outdated data that serves no purpose. This is where Office 365 retention policies come into play, addressing two crucial facets –

1. Retention

When a file or folder is subject to a retention policy, it remains structurally intact. Rather than altering its composition, the policy securely preserves the data, preventing permanent deletion before the retention period expires. Users can access a copy of the data in its designated location –

  • The SharePoint and OneDrive data are saved at the Preservation Hold library.
  • The Exchange mailbox data is present in the Recoverable Items folder.
  • The Teams and Yammer data are saved in the subfolder of Exchange’s Recoverable Items folder with the name of SubstrateHolds.
2. Deletion

This refers to the deletion of the data after the retention period. Retention policy helps you in the following ways –

  • You can easily decide which data can be saved or deleted.
  • You can apply a single policy on a single type of data or the whole organization
  • You can apply policy on some selective data based on specific keywords or types.
How to apply a retention policy?

Here is the brief procedure of creating a retention policy using Office 365 Administrator credentials –

  1. Click Admin button in the menu.
    Admin button in the menu
  2. Under the Reports category, click Security & Compliance option.
    click on Security & Compliance
  3. Click the Exchange admin center option.
    Click on Exchange admin center
  4. Go to compliance management, then select retention policies and click () option.
    Go to compliance management
  5. Provide a name to the policy and click () option to add desired tags.
    Provide a name to the policy
  6. Here you can select more than one retention tag using the Add button and click OK.
    you can select
  7. Click Save button.
    Click Save button
  8. A new retention policy is created.
    new retention policy
How does retention policy affect the data?

The retention policy has no immediate impact on the data. When you designate a data location within the retention policy, the data remains in place. Users can continue working with the data without any noticeable alterations in its attributes. However, if a user intentionally or inadvertently deletes the data, a copy is promptly preserved.

Deleted data from sites is archived in the Preservation hold library, while messages and public folders have their deleted data stored in the Recoverable Items folder. These locations provide robust security, and they often go unnoticed by most users.

NOTE: If you have applied retention policy for Office 365 Groups, then it will include both mailboxes and sites.


So far, you’ve learned about retention policies, their functionality, and how to create them. It’s crucial to note that retention policies have a specific time frame, and once they expire, they no longer retain data copies. In such cases, deleted data won’t be recoverable. There is a manual procedure to migrate the emails from Office 365 to Outlook, but to increase the security of data and make it ever lasting, you can use a professional Office 365 backup too which can save the data at a secure location. Kernel Export Office 365 to PST software simplifies this process, enabling you to access and securely store your Office 365 mailbox data in PST files. You can selectively choose important data, and the software generates separate PST files for each mailbox.