eDiscovery Office 365: Tools, Benefits and Best Practices

What is Office 365 eDiscovery?

Microsoft Office 365 e-discovery provides capabilities for the process of identifying, collecting, reviewing and exchanging electronic information for use as evidence in legal cases.

How does Microsoft 365 eDiscovery work?

e-Discovery tools in Office 365 enable users to search for content in Exchange Online mailboxes, Office 365 Groups, SharePoint Online, Microsoft Teams, and OneDrive for Business sites as well as Skype for Business conversations. There are three solutions in Office 365 e-discovery:

• Content search – Enables users to search for content across data sources in Microsoft 365 and export results locally.
• Core e-discovery – Allows users to create eDiscovery cases and assign managers to them. An expansion of eDiscovery’s basic search and export capabilities, Core lets users place an eDiscovery hold on content locations pertinent to the case.
• Advanced e-discovery – Enhances the existing case management, preservation, search, and export capabilities available in Core. Provides an end-to-end workflow to help facilitate critical aspects of the eDiscovery process. Advanced eDiscovery lets legal teams manage custodians, collect and copy data from live service into review sets, and filter, search, and tag content to help users identify and focus on only the most relevant content.

How to simplify Office 365 eDiscovery 

For legal and IT teams who must manage multiple Office 365 legal hold and e-discovery requests, native Office 365 e-discovery tools for email may not provide sufficient flexibility, granularity or ease of management.

Email plays a critical evidentiary role in legal proceedings today. As the primary medium for business communication, email can be used to document an individual's knowledge and motivation as well as the timing and intent of actions and business transactions. Many regulatory frameworks have strict guidelines for email retention and e-discovery, and legal teams and IT administrators can easily be overwhelmed with Office 365 e-discovery requests and Office 365 legal hold requirements.

The right e-discovery tools can help to dramatically reduce the time and resources required to respond to legal and compliance requests. And while the Office 365 e-discovery tools included with the Microsoft platform may be adequate for some companies, many organizations are turning to Office 365 security compliance and archiving solutions from Mimecast to streamline and accelerate Office 365 e-discovery.

Office 365 eDiscovery with Mimecast

Mimecast’s governance and compliance platform helps reduce the cost and complexity of Office 365 eDiscovery. Mimecast Cloud Archive provides a centralized, cloud-based archive for live and historical email, allowing organizations to manage litigation holds and run near real-time searches from one repository.

To protect email data, Mimecast stores three tamper-proof and encrypted copies of every message in multiple data centers. It also captures email content, metadata, proof of delivery, non-repudiation details, original messages, and policy-mandated changes. This preserves complete conversation threads, deleted messages, edit histories, and forensic context across captured platforms.

Unlike Microsoft Purview, which may require a separate escalated eDiscovery case to view deleted or edited messages within a compliance review thread, Mimecast preserves that context from the moment of capture. Legal and compliance teams get a clearer record of what was said, changed, deleted, and preserved.

With rapid, granular search and a single web-based console, Mimecast helps accelerate early case assessment and simplify eDiscovery management. Administrators can manage multiple litigation holds, support SEC 17a-4 compliance and other regulatory requirements, and automate email retention policies across the organization.

Mimecast’s purpose-built AI models, trained on enterprise communication patterns, analyze sentiment, language, and content to surface relevant messages faster during eDiscovery review. This reduces false positives and helps legal teams spend less time sorting through irrelevant results.

Modern eDiscovery also extends beyond email. Mimecast captures and preserves communications from Microsoft Teams, Slack, Zoom, and other collaboration platforms in real time through native API integrations, maintaining message context, edit histories, conversation threading, metadata, and native formats.

Mimecast is also recognized as a Leader in the 2025 Gartner® Magic Quadrant™ for Digital Communications Governance and Archiving Solutions, with recognition tied to its unified AI-driven risk visibility, proactive behavioral anomaly detection, and platform architecture.

Advantages of Office 365 eDiscovery with Mimecast

When you choose Mimecast to manage Office 365 e-discovery, you can:

• Reduce the cost and complexity of managing e-discovery and litigation holds.
• Implement a SaaS-based solution for Office 365 e-discovery quickly and easily.
• Ensure that e-discovery activity is fully auditable.
• Accelerate e-discovery with industry-leading search tools.
• Accelerate search, results, and export, with testing showing Mimecast completed eDiscovery tasks 6.7x faster than Microsoft Purview.
• Use AI-assisted search and review to reduce false positives and surface relevant communications faster.
• Preserve deleted messages, edit histories, metadata, and full conversation context across captured platforms.
• Capture collaboration data through native API integrations without losing conversation context or metadata.
• Export directly to Relativity and other legal review platforms with native format support.

Learn more about Office 365 e-discovery and Mimecast, and about Mimecast healthcare compliance solutions.