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Email archiving vs. backup: two tools, two completely different jobs

The mailvault365 team 6 min read

"We back up our email, so we're covered." It's one of the most common sentences in small-business IT — and one of the most expensive misunderstandings. Backups and archives look similar from a distance (both keep copies of your mail somewhere else), but they answer two completely different questions. Confusing them is how companies end up confidently holding the wrong tool when it matters.

Two questions, two tools

A backup answers: "Something broke — can we get it back?" It protects against disasters: a deleted mailbox, a ransomware incident, a botched migration. To do that job well, a backup takes periodic snapshots and keeps them for a limited time.

An archive answers: "Can we prove what was sent and received?" It protects against a different kind of problem: a customer disputing an agreement, an auditor requesting correspondence, a retention obligation. To do that job well, an archive captures every single message, keeps it unchanged, and makes it findable years later.

Backup and archive side by side: snapshots for recovery vs. a complete, immutable record Backup "Can we get it back?" Mon snapshot Tue snapshot Wed snapshot point-in-time copies • mail deleted between snapshots: missed • old snapshots expire and are replaced • restore = admin task, whole datasets • contents restorable, then editable Archive "Can we prove it?" every message, captured as it arrives • complete — nothing between snapshots • kept for years, tamper-proof • full-text search, self-service • originals stay unchanged, provable
Snapshots protect against disasters. A continuous, immutable record protects against disputes.

Where backups quietly fail as archives

Imagine an email arrives on Monday at 10:00 and is deleted on Monday at 15:00. Your nightly backup never saw it. For a backup, that's fine — its job is recovering systems, not preserving individual messages. For a retention obligation or a legal dispute, that email effectively never existed.

Three structural gaps, independent of the backup product:

  • Completeness. Anything received and deleted between snapshots is simply not in the backup.
  • Retention. Backups rotate. The snapshot containing that 2022 email chain was probably overwritten long ago — most backup retention is measured in weeks or months, while email retention obligations are commonly measured in years.
  • Provability. A restored mailbox is just a mailbox again — mail in it can be edited or deleted before anyone looks at it. An archive's value is precisely that nobody, including admins, could change the record.

Where archives don't replace backups

The confusion cuts both ways. An email archive preserves messages — it doesn't restore your SharePoint sites, OneDrive files, or Teams configuration after an incident. If you'd struggle to recover from a wiped tenant, that's a backup conversation, and an archive won't have it for you.

What this means for Microsoft 365 tenants

Microsoft 365 itself sits in an awkward middle: built-in redundancy is not a backup you control, and the built-in "archive" features are not a complete archive unless carefully configured with the right licenses. So the practical checklist looks like this:

  1. Decide how long you want to keep email (how long should a business keep email?).
  2. Put a real archive in front of them: every message captured on arrival, immutable, searchable.
  3. Treat backup as a separate decision about disaster recovery — for email and for the rest of your tenant.

For the archiving half, mailvault365 is the five-minute version: connect your Microsoft 365 tenant, and every mailbox is archived continuously and tamper-proof — with full-text search that lets people find their own mail instead of filing tickets.

Archive your Microsoft 365 email the easy way

mailvault365 archives every mailbox in your tenant automatically — tamper-proof, searchable, nothing to install. 14 days free, no credit card, then $4 per mailbox per month.

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