Purview eDiscovery — standard vs premium
How Purview eDiscovery finds, preserves, and exports content for legal cases — and what premium adds.
Purview eDiscovery is the toolset for legal teams to find, preserve, review, and export Microsoft 365 content for litigation, regulatory requests, and internal investigations. Microsoft offers two tiers — Standard and Premium — and the difference matters a lot for serious cases.
Standard eDiscovery
Available in Microsoft 365 E3 / Office 365 E3, Standard eDiscovery provides:
- Content search across Exchange mailboxes, SharePoint sites, OneDrive accounts, Teams chats, and Viva Engage.
- Case management to organise searches.
- Hold on specific mailboxes and sites, preserving content for the case.
- Export to PST and to standard formats.
It's enough for basic compliance work — a regulator asks for emails between two parties about a specific topic, you search, hold, and export.
Premium eDiscovery
Available in Microsoft 365 E5 and as a Purview add-on, Premium adds:
- Custodian management — tracks individuals, their associated data sources, and hold notifications.
- Legal hold notifications with acknowledgment tracking.
- Communication compliance integration to follow conversations across workloads.
- Advanced indexing of file content and email metadata.
- Conversation reconstruction — Teams chats reassembled into a coherent conversation, not isolated messages.
- Near-duplicate detection and email threading to reduce review volume.
- Predictive coding — ML-driven relevance ranking that trains on reviewer decisions.
- Review sets with annotations, redactions, and tagging.
- Working set management for very large cases (millions of items).
- Export with metadata in load files for downstream review tools (Relativity, etc.).
For large cases — where review volume is high and the cost of manual review dominates — Premium is dramatically more efficient.
Cloud Attached eDiscovery
For organisations using third-party eDiscovery platforms like Relativity, Cloud Attached eDiscovery keeps Microsoft 365 as the source of truth: data is preserved and processed in Purview, and only the relevant subset is exported to the review platform.
Operational tips
- Practice with non-case data before a real matter arrives. eDiscovery isn't intuitive on day one.
- Build named saved searches for common scenarios (a specific user's mail over six months).
- Set up role groups so legal and compliance teams have eDiscovery roles without broader admin rights.
- Combine with retention policies — eDiscovery searches content that exists, including in preservation hold from retention.
- For Teams chat, ensure retention is sufficient — chats default to 30-day retention on some plans.
Licensing
- eDiscovery (Standard) — Microsoft 365 / Office 365 E3 and above.
- eDiscovery (Premium) — Microsoft 365 E5, Office 365 E5, or Microsoft 365 E5 Compliance add-on.
- Some advanced features require per-user "eDiscovery user licences" rather than tenant-level entitlement.
For legal teams in regulated industries, Premium is rarely optional. For SMBs handling occasional requests, Standard plus a thoughtful retention design is usually enough.