Last Updated on April 1, 2026 Sarah Gayda
Organizations generate vast amounts of email every day—but not all of it should be kept forever.
Without a clear approach to email retention, businesses risk:
- Keeping unnecessary data too long
- Increasing storage costs
- Failing to meet compliance requirements
- Losing control over critical information
As part of a broader email management strategy, email retention ensures that important communications are preserved for the right amount of time—and no longer.
What Is Email Retention?
Email retention is the process of defining how long email messages should be stored before they are deleted or archived.
In Microsoft 365, retention policies are used to:
- Keep emails for a specific period
- Automatically delete emails after that period
- Ensure compliance with legal and regulatory requirements
Retention policies help organizations keep only the information that has business or legal value, while removing content that no longer serves a purpose.
Why Email Retention Matters
Email retention is not just about storage—it plays a critical role in compliance, risk management, and operational efficiency.
1. Compliance and Legal Requirements
Many regulations require organizations to retain business communications for defined periods. Failure to do so can result in fines or legal exposure.
2. Risk Reduction
Keeping emails longer than necessary increases exposure to:
- Data breaches
- Legal discovery
- Sensitive information leaks
Retention policies help reduce this risk by ensuring outdated data is removed.
3. Improved Information Management
Retention policies help organizations:
- Keep important emails accessible
- Reduce clutter in inboxes and systems
- Improve search and retrieval
4. Cost Control
Automatically deleting unnecessary emails reduces storage costs and improves system performance.
In fact, in a recent Colligo webinar poll, 52.5% of participants identified business efficiency as their top reason for retaining email, followed by regulatory compliance and legal protection.
This highlights an important shift—email retention is no longer just about compliance. It is also about improving how organizations manage and access information.
This is why organizations are moving toward more structured and automated approaches to email retention.
How Email Retention Works in Microsoft 365
Microsoft 365 provides built-in tools to manage retention across services like Outlook, SharePoint, and Teams.
Retention policies:
- Apply rules across entire mailboxes or systems
- Define how long data is kept
- Automatically delete or retain content based on policy
These policies are part of Microsoft’s data lifecycle management capabilities and help organizations govern information consistently.
Types of Email Retention Policies
Organizations typically use one of the following approaches:
1. Retain Only
Emails are kept indefinitely or for a defined period and not deleted.
2. Delete Only
Emails are deleted after a certain time without being retained.
3. Retain Then Delete
Emails are preserved for a defined period and automatically deleted afterward. This is the most common approach in Microsoft 365 environments.
Email Retention vs Email Deletion: What’s the Difference?
Email retention and deletion work together but serve different roles:
- Retention policies define how long emails must be kept
- Deletion policies define what happens after that period ends
A strong strategy requires both an effective retention framework and a clear email deletion policy.
For a deeper look at how retention and deletion work together in real-world scenarios, see these email retention and deletion best practices.
The Challenge with Inbox-Based Retention
Many organizations rely on users to manage email retention manually. This creates problems:
- Users don’t consistently apply policies
- Important emails may be deleted too early
- Unnecessary emails may be kept too long
- No standard governance across teams
Manual retention does not scale and introduces risk.
A Better Approach: Structured Email Retention
To improve retention, organizations should move toward:
- Centralized storage (e.g., SharePoint)
- Metadata-based classification
- Automated retention policies
- Integration between Outlook and SharePoint
This ensures that:
- Important emails are preserved
- Retention rules are applied consistently
- Deletion happens automatically when appropriate
Many organizations improve retention by choosing to save email to SharePoint directly from Outlook as part of their workflow.
Supporting Retention with Email Records Management
Retention works best when combined with structured records management.
For example:
- Important emails are captured and stored in SharePoint
- Email metadata is applied for classification so retention and deletion rules can be applied consistently
- Retention policies are applied automatically
This approach supports a broader email records management strategy by ensuring important emails are captured before deletion.
Best Practices for Email Retention
- Define clear retention periods for different email types, including email attachments
- Align policies with legal and business requirements
- Avoid relying on manual user behavior
- Automate retention and deletion wherever possible
- Regularly review and update policies
- Ensure important emails are captured before deletion
Common Questions About Email Retention
An email retention policy defines how long emails are stored and when they are deleted or archived.
Retention periods depend on legal, regulatory, and business requirements, and can range from months to several years.
Yes. Many regulations require organizations to retain business communications for specific periods.
Yes. Microsoft 365 retention policies allow organizations to automatically retain and delete emails based on defined rules. Ideally, email records should be moved from Outlook to SharePoint with tools like Colligo Email Manager, where they can be managed and retained according to policy.
Take Control of Email Retention
Email retention is a critical part of managing information in Microsoft 365.
Without a clear strategy, organizations risk:
- Compliance failures
- Increased costs
- Loss of control over data
By implementing structured and automated retention policies, organizations can ensure that:
- Emails are kept for the right amount of time
- Important information is preserved
- Unnecessary data is removed
Solutions like Colligo Email Manager help organizations capture and manage email in SharePoint, ensuring that retention policies are applied consistently and effectively.
Automation tools like Auto-File can also help ensure emails are captured and stored before deletion policies are enforced.