Exchange Online archive and litigation hold basics

Overview

Archiving and holds protect data for legal and regulatory needs—but increase storage cost and complexity.

Concepts

• Archive mailbox: extended storage tier when enabled per mailbox.
• Litigation Hold: preserves mailbox immutably for eDiscovery—do not enable casually.
• Retention policies/labels: preferred for broad retention vs per-mailbox holds when possible.

Operational guidance

1. Legal/compliance defines retention; IT implements via Purview—not the reverse.
2. Never delete users with active holds without migration plan.
3. Use eDiscovery cases for targeted searches; track case owners.

Cost

Model auto-expanding archive growth in multi-year forecasts.