Moving from MailStore to a cloud archive: what to consider

MailStore has archived email reliably in tens of thousands of companies — ours isn't a story of a bad product. The story is usually about the server underneath it: the Windows machine that needs patching, the storage that needs planning, the backups that need checking, and the one person who knows how all of it fits together. When that person changes jobs, or the hardware ages out, or email moves fully into Microsoft 365, the question comes up: does the archive really still need its own server?

What actually changes with a cloud archive

Functionally, both approaches archive email. What moves is responsibility: updates, storage, monitoring, and the archive's own backups stop being your team's job. What you give up is equally real: the archive no longer sits on hardware you control, and a subscription replaces a license you already own. Whether that trade is good depends on your constraints — we wrote an honest side-by-side here: mailvault365 vs. MailStore, including the cases where staying self-hosted is the right call.

Five things to check before you switch

1. Export format — yours and theirs. Insist on a standard format (.eml) on the new side, so leaving is always possible. And check what exporting your existing archive involves, because that history needs a path forward too.
2. Immutability. Your current archive likely supports retention requirements for unalterable storage. The replacement must too — "stored in the cloud" alone says nothing about whether an admin can quietly delete messages.
3. The access model. Who sees whose archive? Look for: users see their own mailbox by default, wider access is an explicit grant, and cross-mailbox access is logged.
4. Where the data lives. If your policies require European hosting, confirm it (and get it in writing) before migrating a decade of correspondence.
5. Leaver behavior. A key reason archives exist: mailboxes of departed employees. Confirm the archive survives account deletion and what that costs per retained mailbox.

How the migration actually works

In practice, a switch has two independent parts — and that's the reassuring bit:

• From day one: connect the new archive to your Microsoft 365 tenant, and everything currently in your mailboxes — history included — is imported and archived automatically. For mail that still lives in M365, there is no migration project at all.
• The old archive: mail that exists only in your MailStore archive (deleted from mailboxes long ago) needs a migration path — typically an export from the old system that gets imported into the new one. This is the part to discuss with the new provider before committing; with mailvault365, you contact us and we work out the import together.

A practical pattern many companies use: run both in parallel for a transition period. The new service archives everything from day one; the old server stays read-only until its retention obligations expire or its history is migrated — then it's finally, genuinely, switched off.

Want the detailed comparison first? Start here: MailStore alternative for Microsoft 365 — an honest comparison. Or see it with your own mailboxes: 14 days free, no credit card, no sales call.