Microsoft Exchange Online: Transitioning to Unified Audit Logs

Big news for Exchange Online users: Microsoft is making significant changes to its audit logging functionality, and with change comes a mix of opportunity and challenge. In a modern world where security and compliance are critical, audit logs act like your IT department’s black box—providing vital information about events within your Microsoft 365 environment. Here's a detailed breakdown of these changes, what they mean, and why they matter to every Microsoft 365 admin out there.

---

The Headline: Legacy Audit Cmdlets Are Being Retired​

Microsoft has announced its plans to formally retire the Search-MailboxAuditLog and New-MailboxAuditLogSearch cmdlets in Exchange Online, effective March 2025. These two cmdlets have long been staples for Exchange Online admins tasked with keeping tabs on audit logs in their organization, but times (and technology) change.
Here’s the kicker: Instead of simply scrapping them, Microsoft is pushing admins to adopt the Search-UnifiedAuditLog cmdlet. Why? Because it consolidates audit logs across multiple products in the Microsoft 365 ecosystem, including Exchange Online, Teams, SharePoint Online, OneDrive for Business, Power BI, and more.
This isn’t just about throwing old tools out the window—it’s about modernizing how logs are accessed, searched, and utilized in a cloud-first environment.

---

Understanding the Cmdlet Transition​

To appreciate the significance of these changes, let’s take a closer look at the cmdlets being retired and their replacement:

1. Goodbye to Search-MailboxAuditLog​

This cmdlet has been popular for performing synchronous searches of mailbox audit logs. Any admin who needed quick results to troubleshoot or investigate specific mailbox events could rely on this tool to provide data directly in their Exchange Management Shell.

2. Farewell to New-MailboxAuditLogSearch​

Unlike its counterpart above, this cmdlet handles more complex search queries asynchronously and sends the results directly to designated recipients via email. Ideal for scenarios requiring collaboration or distribution of search outputs.

3. Hello, Search-UnifiedAuditLog​

The new cmdlet, Search-UnifiedAuditLog, is Microsoft’s answer for centralized and unified logging. This cmdlet takes audit log searches several steps further:

• Cross-service searches: Pull logs not just from Exchange Online but also from Teams, SharePoint, and many other Microsoft 365 services.
• Advanced filtering: Sort records using multiple parameters like user, date range, action type, or even IP address.
• Consolidation: One cmdlet to rule them all, eliminating the need for separate tools across services.

Timeline of the Migration​

• March 1, 2025: Microsoft will stop writing new log entries to the retiring cmdlets. From this point onward, all new logs will exclusively flow through the Search-UnifiedAuditLog cmdlet.
• Late June 2025: While the old cmdlets will remain accessible for historical data until this date, after June 2025, they’ll essentially become read-only artifacts of the past. No further changes or downloads will be allowed.

---

Why the Change Matters​

Here’s where things get interesting. On the surface, this change seems like a simple tooling update. But underneath the hood, it reflects several trends shaping the world of IT administration:

1. Unified Audit Logs Are Key to Cloud Operations​

In modern cloud environments, organizational boundaries blur. Employees often switch between Teams, SharePoint, and Outlook seamlessly, with business data flowing across these services. A unified logging mechanism enables admins to track activity regardless of the platform.

2. Enhanced Security and Compliance​

With cybersecurity threats evolving daily, the ability to slice and dice audit data by specific actions, users, or source IPs (hello advanced filtering!) isn’t just a nice-to-have—it’s essential.
Suppose an attacker gains access to a user’s account. With Search-UnifiedAuditLog, admins can more easily pinpoint unusual login patterns, identify unauthorized changes, and analyze lateral movements across multiple tools like Teams or SharePoint.

3. Simplifying Admin Workflows​

Gone are the days of jumping between cmdlets for different services. By consolidating logs into a single place, Microsoft is cutting down on complexity, which ultimately reduces overhead and admin burden.

---

Preparing for the Transition​

If you’re an Exchange Online admin, here’s what you need to do to get ahead of these changes:

1. Embrace the Unified Audit Log​

Begin familiarizing yourself with the Search-UnifiedAuditLog cmdlet today. Microsoft is already encouraging its use, so don’t wait until the last minute. Start running parallel searches between the old and new cmdlets to ensure your scripts and workflows transition smoothly.

2. Enable Audit Logging in your Tenant​

The new cmdlet requires audit logging to be enabled in Microsoft 365. Double-check your tenant’s audit logging settings to avoid surprises when the time comes.

3. Train Your Team​

If your IT team actively uses the legacy cmdlets, make sure they’re up to speed with the Search-UnifiedAuditLog command. Proper training avoids downtime and ensures seamless adoption.

4. Review Compliance Needs​

Audit logs are often essential for regulatory reporting or internal governance. If your organization relies on the output of these cmdlets, assess how the new cmdlet will fit into your compliance strategies.

---

What Does the Future Hold?​

This change is part of a broader push by Microsoft to unify its tools under a cloud-first strategy. Expect continued integration between Microsoft 365 services, and anticipate more powerful features down the road for audit logging and reporting.
But let’s not sugarcoat it—change always brings challenges. Legacy scripts relying on the old cmdlets? Broken until updated. Admins unfamiliar with the new tooling? Expect a bit of a learning curve. However, the long-term gains in operational efficiency, security, and scalability are hard to ignore.
Microsoft’s messaging is clear: The future is unified, automated, and, ideally, simpler for IT admins. Get ready to log (and search) smarter, not harder.

---

Have Thoughts? Let’s Discuss​

Are these changes exciting or frustrating for you? Have a favorite or indispensable PowerShell script relying on the old cmdlets? Join the discussion and share your insights, challenges, and tips with the WindowsForum.com community!

---

Source: Petri IT Knowledgebase https://petri.com/exchange-online-audit-logging-changes/