Hyper Backup creates a snapshot of the entire Synology NAS including the MailPlus Server database. To recover a single deleted email or a single corrupted mailbox from Hyper Backup, you restore the entire NAS to a previous state overwriting all data changed since that backup. MBOX export creates a separate mailbox-level backup: individual accounts can be restored independently, without touching any other user’s data or any other part of the NAS. The correct approach is to run both: Hyper Backup for system-level recovery and regular MBOX exports for mailbox-level recovery. Use Univik Synology MailPlus Converter to convert MBOX backups to PST or PDF for long-term storage independent of the NAS.
Two Kinds of Email Backup: System vs Mailbox-Level
Backing up a mail server requires two different kinds of protection and most MailPlus Server deployments only implement one of them.
System backup protects against hardware failure, NAS corruption or accidental deletion of the mail server itself. If the NAS fails, a system backup restores the entire thing DSM, all packages including MailPlus Server, all user data and all email. Hyper Backup does this.
Mailbox-level backup protects against targeted email data loss a user accidentally deletes their Inbox, a mailbox is corrupted, a former employee’s email archive needs to be recovered after the account is deleted. Mailbox-level backup lets you restore one user’s email without touching anything else on the NAS.
Hyper Backup is a system backup tool. It does not provide mailbox-level recovery. MBOX export is the mailbox-level backup. Both are necessary because they protect against different failure modes that the other cannot handle.
Why Hyper Backup Alone Is Not Enough
Hyper Backup stores NAS snapshots. Each snapshot captures the entire state of the NAS at a point in time drives, DSM, all packages and all user data including the MailPlus Server email database.
Restoring from Hyper Backup means restoring the entire NAS to that snapshot. Any data created or changed after the snapshot date is lost. If today is April 15th and the most recent Hyper Backup ran on April 8th, a full restore loses a week of data for every user and every service on the NAS not just email.
For the specific scenario of email recovery, this creates two problems:
Collateral damage to unrelated data. Restoring the NAS to recover one user’s deleted email overwrites a week of shared folder changes, file server activity and every other MailPlus account’s email. The user asking for their recovered email gets it every other user on the NAS loses a week of work.
Operational disruption during restore. A full NAS restore from Hyper Backup takes the entire system offline during the restore process. For a NAS running email, file server and other services, this means a significant outage across all services for a problem that only affected one email account.
Most IT admins who have only Hyper Backup configured discover these limitations the first time someone requests email recovery. The right response is not to use Hyper Backup for that recovery it is to have a mailbox-level backup that was designed for exactly this scenario.
MBOX Export as a Mailbox-Level Backup
The MailPlus Server admin MBOX export the same export used for migration projects is also the correct tool for mailbox-level backup. Each export produces a folder containing one MBOX file per account folder, preserving the complete email content and folder structure at that point in time.
When a mailbox recovery is needed, the process is surgical:
Identify the MBOX backup that predates the data loss. If a user accidentally deleted email on March 20th, the most recent MBOX backup from before March 20th contains the deleted messages.
Open the relevant MBOX file and locate the lost email. Load the account’s INBOX.mbox or relevant folder MBOX into Univik Synology MailPlus Converter or ImportExportTools NG in Thunderbird. Browse to the deleted email.
Export and deliver the recovered email. Export the specific email as EML or as a PST containing only that message. Send to the user or import back into their MailPlus account. The NAS stays online. No other users are affected. The entire recovery takes minutes once the right MBOX backup file is located.
How Often to Back Up
MBOX backup cadence depends on how much email data loss is acceptable if a recovery is needed. The relevant metric is the recovery point objective the maximum amount of email you can afford to lose. If a user could lose a week of email without major consequences, weekly MBOX exports are sufficient. If losing even a day of email is unacceptable, daily exports are required.
| Organisation Type | Recommended MBOX Export Frequency | Rationale |
|---|---|---|
| Home or personal NAS | Monthly | Personal email loss is inconvenient but low impact |
| Small business, low email volume | Weekly | Balances storage overhead with acceptable recovery point |
| Active business with customer communications | Daily | Customer-facing email loss has direct business impact |
| Regulated industry (legal, medical, financial) | Daily with 7-year retention | Regulatory retention obligations apply to email |
Keep multiple MBOX snapshots rather than overwriting the previous backup each time. A rolling set of four weekly backups plus the previous month’s export means you can recover email from any point in the last four weeks, plus a monthly reference point going back further.
Setting Up the Backup Workflow
Create a dedicated shared folder for email backups. In DSM, create a shared folder named MailPlus-Backups on a volume with sufficient free space. Structure the folder with dated subfolders for example MailPlus-Backups/2026-06-01, MailPlus-Backups/2026-06-08 and so on. This makes browsing backup history easy when a recovery is needed.
Run the admin MBOX export to the dated subfolder. In MailPlus Server, go to Storage then Back Up. Set the destination to the current date’s subfolder in MailPlus-Backups. Export all accounts. See the export guide for the full step-by-step process.
Automate with a DSM task scheduler if available. DSM’s Task Scheduler (Control Panel then Task Scheduler) can run shell scripts on a schedule. MailPlus Server 3.x and 4.x include command-line tools for triggering exports. Your Synology Knowledge Base or community forums have script examples for scheduled MailPlus export this is worth setting up for weekly or daily automated exports so backups happen without manual intervention.
Copy the MBOX backup to an external location. A backup that only exists on the NAS is not a backup it is a copy. If the NAS fails completely (drive failure, water damage, theft), the MBOX backup on the NAS fails with it. Configure Hyper Backup or Cloud Sync to copy the MailPlus-Backups folder to an external destination an external drive, another NAS or cloud storage. Two independent copies is the minimum standard.
Prune old backups on a retention schedule. Define how long to keep each backup tier. For example: keep the last four weekly backups, keep the first backup of each month for one year and delete monthly backups older than one year. Prune manually or via a DSM scheduled script. Without pruning, the backup folder grows indefinitely.
Where to Store the MBOX Backup
Second Synology NAS (best for organisations). Synology’s Hyper Backup can replicate the MailPlus-Backups folder to a second NAS at another location. This gives geographic redundancy a fire or flood that destroys the primary NAS does not affect the backup NAS.
Cloud storage via Cloud Sync. Synology Cloud Sync can sync the MailPlus-Backups folder to AWS S3, Backblaze B2, Microsoft Azure, Google Cloud Storage or similar services. MBOX files are plain text they compress well and storage costs are low. A 50 GB monthly MBOX backup archive costs a few dollars per month in cloud storage.
External USB drive (minimum viable for personal use). Connecting an external USB drive to the NAS USB port and copying the MailPlus-Backups folder manually is the lowest-cost option. Suitable for personal or home NAS deployments. The limitation: USB drives fail and a manual process relies on someone remembering to run it.
Converting the Backup for Long-Term Storage
MBOX files are the right format for active backup use they are readable by conversion tools and can be imported back into MailPlus Server or Thunderbird for recovery. For long-term archival storage (three or more years), converting MBOX backups to PDF is worth considering.
PDF offers two advantages over MBOX for archival: it is universally readable without any mail client or converter software and it cannot be accidentally modified. A PDF archive of email from 2019 will be readable in 2035 regardless of what email software exists then. A 2019 MBOX file requires a current converter or mail client to be useful.
For annual archiving, run an MBOX export at year end and convert it to PDF using Univik Synology MailPlus Converter. Store the PDF archive in a separate long-term storage folder. Keep the MBOX version for the most recent 12 months for active recovery use.
Recovery Scenarios: Which Backup Handles What
| Failure Scenario | Hyper Backup | MBOX Export |
|---|---|---|
| NAS drive failure entire system needs rebuilding | ✅ Full NAS restore | ❌ Cannot rebuild MailPlus Server itself |
| DSM corruption system needs to be reinstalled | ✅ System restore | ❌ Cannot restore DSM |
| One user accidentally deleted all their email | ⚠️ Full NAS restore affects all users | ✅ Restore that user’s MBOX only no other user affected |
| One mailbox corrupted | ⚠️ Full NAS restore required | ✅ Restore that mailbox from MBOX backup |
| Former employee’s email archive needed months later | ⚠️ Only if Hyper Backup retains that far back | ✅ MBOX export from before account deletion |
| Specific email needed for legal discovery | ⚠️ Requires full restore to locate | ✅ Open MBOX in converter, search and export specific email |
| NAS decommissioned preserve email permanently | ❌ Backup is useless without NAS to restore to | ✅ Convert MBOX to PDF/PST independent of NAS |
Frequently Asked Questions
Does MailPlus Server have a built-in backup scheduler?
MailPlus Server includes a backup function that exports mailboxes to MBOX files. However, it does not have a fully automated scheduler within the MailPlus Server interface itself. Automation requires using DSM’s Task Scheduler to run a script that triggers the MailPlus export on a schedule. Synology’s knowledge base and community forums have examples of the relevant shell commands for automating MailPlus Server exports via Task Scheduler.
Can Hyper Backup protect individual emails without a full restore?
Not easily. Hyper Backup captures the MailPlus Server database as a binary blob. To access individual email within it, you would need to restore the full NAS to a previous state and then extract the email from the running MailPlus Server after restore. There is no tool that reads individual email messages directly from a Hyper Backup archive without going through a full restore first. This is why MBOX export is the right tool for individual email recovery.
How large are MBOX export files compared to the in-MailPlus email size?
MBOX files are typically close to the size shown in MailPlus Server’s Storage view. Attachments account for most of the storage. A 40 GB MailPlus Server email database typically produces 35 to 45 GB of MBOX files compression varies depending on attachment types. Text-heavy email archives compress more than attachment-heavy ones.
What happens to the MBOX backup if the NAS drive fails during export?
An incomplete export produces partial MBOX files. These partial files may be importable but will be missing email from after the point of failure. Always verify a backup immediately after it completes check that all account folders are present and that MBOX files are non-zero in size. If the export fails mid-run, re-run it as soon as the NAS is stable.
Should I encrypt the MBOX backup?
Yes, if the backup is stored outside the NAS particularly if it goes to cloud storage or is transported on removable media. MBOX files contain the full text of every email including sensitive communications, attachments and confidential information. Encrypt cloud-stored MBOX backups using server-side encryption (most cloud storage providers offer this) or client-side encryption before upload. Synology Drive and Hyper Backup both support client-side encryption for cloud destinations.
Conclusion
Hyper Backup and MBOX export protect against different failure modes. Neither replaces the other. A MailPlus Server deployment that only has Hyper Backup is exposed to targeted email data loss scenarios where a full NAS restore is the only recovery option with all the collateral damage that entails.
Adding regular MBOX exports takes 30 minutes to set up and a few hours per run for a typical business deployment. It transforms a full-restore-or-nothing recovery situation into a surgical, per-mailbox operation.
Is your current NAS backup limited to Hyper Backup only? If so, the question to ask is: if a user came to you tomorrow reporting that they accidentally deleted their entire Inbox, how would you recover it and what would that recovery cost every other user on the NAS?