Why Microsoft 365 Is Not the Answer for eDiscovery

Microsoft 365 (M365) is the go-to productivity suite for many organizations and government agencies. So it’s natural to consider Microsoft Purview’s built-in eDiscovery tools — even to the point of considering paying extra for an eDiscovery (Standard) or eDiscovery (Premium) license.

But that convenience comes with shortcomings, pitfalls, and risks.

A true eDiscovery platform should eliminate manual processes, save time, and reduce costs in a secure, user-friendly environment. M365 often fails to deliver on those expectations. Its limitations are well-documented, both in Microsoft’s own support materials and in real-world legal proceedings.

Immediate Shortcomings of M365 for eDiscovery

Before getting into the more serious deal-breakers, M365 presents immediate challenges that make it difficult to use for eDiscovery at scale.

The lack of speed is one of those shortcomings. According to Microsoft, the maximum throughput is 2 GB per hour, and a search of 100,000 mailboxes takes an average of 25 minutes. For larger data sets, those low speeds become a bottleneck, and form one of the biggest complaints for teams trying to meet tight deadlines. The user interface itself is often described as slow and hard to navigate, adding more time to routine tasks.

Data source limitations are another barrier. M365 is notorious for not supporting the data sources you would expect to be able to access. Microsoft lists only 63 file types supported in the highest version of eDiscovery (Premium), and nearly half of those are Microsoft-specific.

Does your organization or agency use Slack or Box? You can’t work with those, as well as many other popular platforms, within M365.

In fact, the vast majority of applications you likely use aren’t supported by M365. According to the Zylo 2025 SaaS Management Index Report, the average organization has approximately 275 SaaS applications. The number increases to 660 for large organizations.

Manual work is another challenge. If you want to use M365 for eDiscovery, you would need to log into unsupported sources and do the work there manually. The process introduces additional risks compared to a full-fledged eDiscovery tool. For instance, Casepoint’s platform can instantly work with and preserve more than 600 native data types securely.

Major Pitfalls: M365 and Search Capabilities

M365 does not properly index data for running content searches. Microsoft lists many scenarios that result in partially indexed items, including unrecognized file types, too many files attached to an email message, and maximum attachment size.

Another major issue is the lack of advanced eDiscovery search functionality. M365 doesn’t accommodate complex Boolean searches, like those with negative operators and advanced wildcard operators, along with “fuzzy logic” searches for relevant documents.

These problems should make you pause when considering using M365 for eDiscovery. After all, performance issues and file support are inconvenient — but risking incomplete or inaccurate search results is a legal risk.

Special Master Criticizes M365’s Search Results in Court Case

In Deal Genius, LLC v. O2Cool, LLC, Special Master Phillip Favro published a report that could influence how courts view the use of M365 to collect electronically stored information (ESI). Specifically, the report raises questions about whether attorneys can meet their obligations under Federal Rule of Civil Procedure 26(g) when relying on M365 search tools.

Favro found that Deal Genius’ efforts “did not satisfy the duty of reasonable inquiry under Federal Rule of Civil Procedure 26(g)(1).” Rule 26(g)(1) requires attorneys to certify that their discovery responses are complete and correct to the best of their knowledge — after making a reasonable effort to verify that it's true.

“As the Special Master understands it, Deal Genius conducted its searches for relevant email on its Microsoft 365 platform,” Favro said in the report. “Microsoft 365 allows users to both generate and maintain data in a cloud-based repository. Microsoft 365 has functionality that allows users to conduct searches for particular information. However, Microsoft 365 has technological limitations that may not allow a responding party to generate reliable search results— as would typically be possible with an electronic discovery platform that has a fully indexed database and an advanced search engine—and thus satisfy the Rule 26(g) reasonable inquiry standard.”

He then listed a few relevant limitations for M365.

• Limited Indexing: “Microsoft 365 generally does not fully index the data encompassed within an organization's Microsoft 365 environment.”

• No Support for Advanced Queries: “Microsoft 365 does not accommodate complex Boolean searches, including certain wildcard operators, proximity operators, or connector terms, nor cannot it handle ‘fuzzy logic’ searches.”

• No Validation of Results: “Microsoft 365 does not allow users to validate their search and production results.”

Favro is a court-appointed special master, expert witness, and trusted advisor, as well as a nationally recognized scholar on electronic discovery.

What Can You Use Instead of M365?

While M365 can be useful for preserving and managing the data generated in the Microsoft ecosystem, using M365 to manage your whole eDiscovery process is likely to cause headaches and potentially introduce legal risks. You’re better off choosing a secure platform that allows you to process, review, produce, and analyze data from any source.

Instead of using M365, opt for a more reliable, application-agnostic eDiscovery solution offering the power, scale, and broad feature set to reliably collect from all your enterprise applications. To achieve the full benefits from a platform, you need a provider and partner that clearly understands these challenges.

Learn how to seamlessly identify, collect, preserve, and discover your legal, regulatory, and compliance data from any source — all in one secure AI-powered platform.