Non-destructive restore by default
Restore in Restow is granular or complete (a single email, a folder, a file, a specific file version, or an entire mailbox or OneDrive), into the original account or a different one. By default it does not overwrite anything that already exists: it writes new items rather than silently replacing live data, because the one thing worse than a missing backup is a restore that destroys something that wasn't actually lost. There is no mode that overwrites: an existing item is kept next to the restored one or skipped.
Self-service, and restore for others
Today, end users sign in with a passkey or the emergency password with TOTP and can restore only their own mailbox or OneDrive, with no admin ticket required for the common case. Signing in with a Microsoft account through Entra OIDC is built into Restow but not enabled yet: the button exists, but ownership today would be bound to the email claim alone, with no verified Microsoft tenant/user binding: a real security gap this project is not willing to ship, not just a flag to flip. Restoring on someone else's behalf needs the Global Admin role for that tenant, or a Provider Admin role in the Service Provider edition; every such restore is impersonation, and in every edition every impersonation is written to Restow's tamper-evident, hash-chained audit log: who ran it, when, for whom, and from which IP. The viewer for that log, with search, details and chain verification, is part of Business and Service Provider and still in development.
Browsing before you restore
The restore explorer lets you look at a backup before anything is written. A slim timeline of restore points runs along the bottom of the screen, with the newest one centred, so you can move between points in time. A folder without subfolders says so.
Restoring from mail files and from machines
A mailbox imported from mail files (see mail import and export) can be restored into a Microsoft 365 or IMAP mailbox, or downloaded. It has no original account, so restoring to the original is not offered for it. A server or client backed up with the agent (see server and client backup) is restored into a new folder on that machine, never over existing files, or downloaded as a ZIP.
Where "non-destructive by default" is going next
For OneDrive files, an optional "Replace" mode is planned: the current file would become an earlier version in OneDrive's own version history, so nothing is deleted. Mail, calendar and contacts will never be overwritten. Full, per-item restore verification (reading back and checking every backed-up item, not a weekly sample) is the other piece of "restore that's actually proven," covered on the verification page.
Frequently asked
Can a Restow restore overwrite my existing mail?
By default, no. Restore writes items into the target (the original account or a different one) rather than silently replacing what's already there. There is no mode that overwrites: the API refuses one, so an existing item is always either kept next to the restored one or skipped.
Who can restore data for someone else?
Today, end users sign in with a passkey or the emergency password with TOTP and can only restore their own mailbox or OneDrive. Signing in with a Microsoft account (Entra OIDC) is built but not enabled yet: the button exists, but the tenant/ownership binding behind it (today, tied to the email claim alone) isn't safe to turn on. Restoring on behalf of another user needs the Global Admin role for that tenant, or Provider Admin, and every such restore (impersonation) is written to Restow's tamper-evident, hash-chained audit log in every edition: who, when, for whom, from which IP. The viewer for that log (search, details, chain verification) is part of Business and Service Provider and still in development.
What can be restored: a whole mailbox, or a single email?
Both, and everything in between: a single email, a folder, a file, a specific file version, or a complete mailbox/OneDrive, from any point Restow has a backup for.
Can I restore from something other than a Microsoft 365 or IMAP backup?
Yes. A mailbox imported from mail files (EML, MSG, MBOX, a MailStore export) can be restored into a Microsoft 365 or IMAP mailbox, or downloaded. A server or client backed up with the agent can be restored into a new folder on that machine, never over existing files, or downloaded as a ZIP.