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Microsoft 365 backup without a subscription

By Lucas Flores, IT Systeme Flores UG. Last updated 2026-10-22

Restow is Microsoft 365 backup with a one-time license. It runs on your own Linux server, writes encrypted backups to storage you choose and proves every week that they can be restored. Community is free; Business costs €595 once for one organization, Service Provider €1,950 for any number of tenants. There is no fee per mailbox and nothing renews automatically; from version 1.0, updates after the first 12 months are an optional update year (Business €295, Service Provider €595 net per year), explained below.

Subscription or one-time purchase: the models side by side

Each line links to a comparison page that cites the vendor's own sources with the date they were read. Prices are list prices before tax and discounts.

Why the license model matters for a backup

A backup is only useful on the day you need a restore, possibly years after you set it up. With a subscription, that restore path depends on a bill being paid on time and on a price you do not control at the next renewal. With a one-time license the software you bought keeps running, and the backups sit on your own storage in a format you can read without the vendor.

The longer reasoning, with sources, is in The subscription trap in backup pricing and the worked numbers in per-user pricing over 5 years.

What the license includes

• Pre-sale licenses include every 1.x update; from version 1.0, a license includes 12 months of updates, then an optional update year (Business €295, Service Provider €595 net per year).
• Without an update year, every version released until then keeps running with all modules, but gets no more security fixes. After a gap, the next update year costs the normal price, with no back payment.
• If development ever ends, twelve months' notice, and the Business and Service Provider modules are published as open source under Apache 2.0.
• No mailbox limit and no user count: Business covers one organization, Service Provider any number of tenants.
• A signed key checked offline: no phone-home and no license server that could switch the software off.
• Not included: support, setup, operation and SLAs, which need a separate contract.

Does Restow have recurring costs too?

Restow is not free of recurring costs either, and says so: from version 1.0, a license includes 12 months of updates, then an optional update year at a fixed price per edition (Business €295, Service Provider €595 net per year). Three things differ from the per-user subscriptions above:

• there is no price per user or mailbox;
• a gap costs nothing extra, because the next update year is the normal price and there is no reactivation fee;
• the software does not depend on it. Without an update year, every version released until then keeps running with all modules, restores included.

What you give up is newer versions and their security fixes.

What Restow does not do yet

Restow is a beta: run it beside an existing backup until you have verified restores against your own data. It backs up Exchange Online mail, calendar and contacts, OneDrive, SharePoint Online sites (since 0.4.0), the calendar and conversations of Microsoft 365 groups (since 0.4.5, opt-in), IMAP mailboxes, SMB and NFS file shares and Linux and macOS machines; Teams chats are not backed up. See the Roadmap.

Frequently asked

All prices and terms · Restow compared with 14 vendors · What Microsoft 365 backup costs per user · Does Microsoft 365 back up your data?