In short
Email archive migration means moving mail from an old archive or PST and EML files into a new archive. NinjaOne offers an ingestion service, which it says it provides at no charge, for zipped EML or unzipped PST files uploaded to an Amazon S3 bucket with a mapping file. Journaling then captures new mail from the day it starts.
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What archive migration covers
Most organisations arrive at a new archive with history. Typical sources:
- An older on-premises or hosted journaling archive being retired
- An export from a previous cloud archiving provider
- PST files from leavers, kept on file shares or laptops
- Exports made for a past dispute or audit that were never put anywhere searchable
The aim is to get that mail into NinjaOne Archiver, where it sits under the same retention policies, eDiscovery search and legal hold as everything else.
This is not PST-to-mailbox migration, where old mail is loaded back into users' live Outlook or Gmail mailboxes. That is a different job with different tools. NinjaOne also says it does not recommend using SaaS Backup as a migration tool. Archive migration puts history into the archive, not back into mailboxes.
New mail and old mail: two different routes
Two things fill an archive, and it helps to keep them apart:
| How it gets into NinjaOne Archiver | From when | |
|---|---|---|
| New mail | Email journaling copies incoming and outgoing messages as they pass through Microsoft 365 or Google Workspace | From the day journaling is switched on |
| Mail already in current mailboxes | The initial backup when each mailbox is added | Whatever is still in the mailbox at that point |
| Mail outside current mailboxes | NinjaOne's email ingestion service, from EML or PST files | Whatever the old archive or files contain |
Journaling does not reach backwards. Mail that users deleted before journaling started, and mail that only exists in an old archive or a leaver's PST file, comes in only through ingestion. That is why archive migration is part of most new archive projects rather than an afterthought.
Not sure which option applies to you? Ask us
Tell us about your organisation and we will point you to the right option.
How NinjaOne's ingestion service works
NinjaOne's documentation describes ingestion as "importing email data in bulk in the form of EML or PST files", and says it "provides this service at no charge" to its customers. The main points:
- Formats: zipped EML files (Zip or Gzip only; 7-Zip is not supported) or PST files, which should not be zipped; other file types are ignored
- Upload: files go into the uploads folder of an Amazon S3 bucket; NinjaOne emails the credentials to the address on the account, and the credential links expire after 7 days
- Mapping file: a comma-delimited file that tells the system where each file belongs
- Start: the process begins with a support request to NinjaOne, and runs automatically once files and mapping are in place
- Not ingested: contacts (VCF) and calendar items (ICAL), even inside PST files
- De-duplication: duplicates may be removed, so the ingested volume cannot be compared with the source as proof of success
NinjaOne is explicit that it does not build, upload or manage the mapping file, and that the customer is responsible for it. Getting the mapping right is where most of the planning effort goes, and it is where we help most.
Archiver ingestion and Non-Archiver ingestion
NinjaOne offers two types of ingestion, and each needs a different mapping file.
| Archiver ingestion | Non-Archiver ingestion | |
|---|---|---|
| Use it when | You cannot tie the mail to a specific current user | You know which files belong to which accounts |
| Where the mail goes | A catch-all account, with the system mapping it there or attempting to match it to individual accounts | Each file goes directly into its designated account |
| Mapping file | File name only | Account ID, email address and file name, with an email account ID where needed |
| Typical source | An old journal archive export, or unsorted PST files | Named PST exports for current staff |
Leavers' mail is often the awkward middle case: you know whose it was, but the account no longer exists. Whether it goes to the catch-all account or to a specific deactivated account is something we decide with you when we plan the import, together with how it will be searched. See what to do with a former employee's mailbox.
Prefer a hand with this?
We can help you plan it and set it up, alongside your own team.
Planning a migration you can defend later
Archived mail is only useful as evidence if you can show where it came from. Before anything is uploaded, plan:
- Inventory: list every source, what it holds, the date range, whose mail it is and roughly how large it is
- Export format: confirm the old system can export to EML or PST, and what metadata survives the export
- Chain of custody: record who exported what, when and how, and keep that record with the project
- Mapping: build and check the mapping file, deciding between catch-all and named-account ingestion for each source
- Retention: NinjaOne counts retention from each message's received date, so older mail may already be past a short retention period; check your policies against the age of the mail before you import it
- Holds: identify any mail under an existing legal hold, so it is held in the new archive before the old one is switched off
- Decommissioning: keep the old archive or files until you have checked that the mail is searchable in the new one, then retire them in line with your retention policy
The retention step catches people out. If your email retention policy says seven years and you import mail that is nine years old, it may be due for deletion straight away, which may be right, or may not be what you intended.
What we do, and what we don't promise
We can supply NinjaOne Archiver and help with the migration around it: the inventory, the export questions for your old system, building and checking the mapping file, raising the ingestion request with NinjaOne, and checking the results with eDiscovery searches once the mail is in. Journaling and retention are set up first, so new mail is captured while the history is brought across.
We do not promise timelines for ingestion; they depend on the volume of mail, the state of the source files and NinjaOne's process. We agree the plan and the checks with you before anything is uploaded. Contact us to talk about moving a legacy archive or PST files into NinjaOne Archiver. Pricing for the archive is by user and bundle: ask us for a quote.
How Forever Systems helps with email archiving
We are an independent UK IT and cyber security provider. We supply NinjaOne SaaS Backup with Archiver for organisations on Microsoft 365 or Google Workspace, and help you get the archive set up, the policies right and the people who need it confident using it.
- Scoping: we look at your mailboxes, leavers, legacy archives and record-keeping obligations, and what your Microsoft 365 or Google Workspace plan already includes, before suggesting anything new
- Set-up: we can configure journaling for Exchange Online or Google Workspace, connect the archive and check that mail is arriving
- Retention and legal hold: we help you turn your email retention policy into archive rules, and show your compliance or HR lead how to search, hold and export
- Leavers and legacy archives: we can help you plan how former employees' mail and older archives are brought across, with the approach confirmed at quote
- Backup alongside the archive: the same NinjaOne per-user licence also covers backup of your Microsoft 365 or Google Workspace data, so recovery and record-keeping are planned together
We work with businesses, schools, charities and public sector organisations. If you also need wider protection, see our independent cloud security guides.
Frequently asked questions
Can I import PST files into NinjaOne Archiver?
Yes. NinjaOne's ingestion service accepts unzipped PST files and zipped EML files, uploaded to an Amazon S3 bucket with a mapping file. Contacts and calendar items are not ingested.
Does NinjaOne charge for email ingestion?
NinjaOne's documentation says it provides the ingestion service at no charge to its customers. Our own help with planning and mapping is confirmed when we quote.
What is the catch-all account in NinjaOne ingestion?
Archiver ingestion puts mail that cannot be tied to a specific user into a catch-all account, where the system maps it or attempts to match it to individual accounts. Non-Archiver ingestion maps each file to a known account.
Will journaling capture my old email?
No. Journaling captures messages from the day it is switched on. Mail already in current mailboxes is taken by the initial backup, and older archives or PST files come in through ingestion.
Is archive migration the same as PST migration to Microsoft 365?
No. PST migration loads old mail back into live mailboxes. Archive migration brings it into the archive, where it is searchable and kept under retention policies. NinjaOne does not recommend SaaS Backup as a mailbox migration tool.
How long does an email archive migration take?
It depends on the volume, the source system and the state of the files, so we do not quote a fixed timescale. We plan the stages and checks with you before anything is uploaded.
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