Convert Mimecast Exports, Split by Account
Native SJF and EJF processing for Aid4Mail Enterprise
Aid4Mail Enterprise reads Mimecast SJF and EJF archives in their native format—no manual unzip. Split a mixed export into one mailbox per account, strip journaling envelopes, and convert to PST.
What Aid4Mail Handles
SJF & EJF, Native
Reads both Mimecast journal formats—no manual unzip
Split by Account
Reorganize a mixed archive into one mailbox per user
De-Journaling
Remove journaling envelopes to recover the original message
Per-Account Output
One PST per account, plus EML, MBOX, or Microsoft 365
Mimecast Archives Are an Awkward Format
Mimecast delivers large SJF and EJF exports—by date range, with users mixed together, wrapped in journaling envelopes. Unzipping and re-sorting them by hand is a massive job.
Manual or Generic Tools
- ⯈ Unzip terabytes of nested archives by hand
- ⯈ Users mixed together by date range
- ⯈ Journaling envelopes wrap every message
- ⯈ A separate tool needed to split by account
- ⯈ Many EML-to-PST converters mishandle the format
With Aid4Mail Enterprise
- ⯈ Reads SJF and EJF natively—no manual unzip
- ⯈ Splits a mixed archive into per-account mailboxes
- ⯈ Strips journaling envelopes during conversion
- ⯈ One PST per account in a single workflow
- ⯈ Concurrent, unattended processing at scale
read natively in Aid4Mail Enterprise—no manual unzip
split a mixed archive into per-user mailboxes
journaling envelopes removed during conversion
Core Conversion Capabilities
Process Mimecast SJF and EJF archives, split them by account, and convert at scale—in the Aid4Mail Enterprise edition.
Native SJF & EJF Reading
Aid4Mail Enterprise reads Mimecast Standard Journal Format (SJF) and Envelope Journal Format (EJF) archives in their native format—no manual unzip.
No manual unzip
Split by Email Account
Reorganize a mixed, date-organized download into one folder per account with the {EmailAccount} template—in a single pass over the archive.
Per-account split
Journaling-Envelope Removal
Turn on Remove journaling envelope to strip the journal wrapper during conversion, so you keep the original message rather than the envelope.
De-journaling
Both Delivery Methods
Handles FTP downloads (ZIP by date range, users mixed) and external-drive delivery (folders usually organized per user) alike.
FTP or drive
Per-Account PST Output
Convert each account folder to its own PST with a wildcard and Session > Duplicate—one output per mailbox, named by email address.
One PST per account
Enterprise Edition
Native Mimecast processing, splitting by account, and multi-session conversion are Aid4Mail Enterprise features.
Enterprise
How Mimecast Conversion Works
A four-step workflow: identify the delivery method, split a mixed archive by account, convert per account, then run concurrently.
Identify Your Delivery Method
FTP downloads arrive as date-range ZIPs with users mixed together; external-drive delivery is usually organized per user. This determines whether you split first.
Native: Aid4Mail reads SJF and EJF in place—no manual unzip either way
Split a Mixed Archive by Account
For a mixed download, run one session with the {EmailAccount} folder template to reorganize the archive into one folder per email account (Target = EML).
Single pass: One session sorts the whole archive—no separate splitting tool
Convert Per Account
Point a session at the per-account folders with a trailing wildcard, set the PST target, then Session > Duplicate to create one session per account.
De-journaled: Remove journaling envelopes during conversion for the original message
Run Concurrently
Run all to process up to 16 sessions concurrently, unattended—one PST per account, named by email address.
Unattended: Queue the batch, then migrate to Microsoft 365 or Google Workspace
SJF, EJF, and Splitting by Account
Mimecast exports come in two journal formats, and usually with every user mixed together. Aid4Mail reads both and reorganizes them by mailbox.
SJF vs EJF, both native
- ✓ SJF (Standard Journal Format): the message as the mailbox received it, without added envelope data
- ✓ EJF (Envelope Journal Format): includes the journaling envelope; Aid4Mail preserves its header data onto the recovered message
- ✓ Aid4Mail Enterprise reads both from a single native Source option
- ✓ Remove journaling envelope strips the journal wrapper, leaving the original message
Split a mixed archive by account
- ✓ Mixed FTP downloads combine every user’s mail, organized by date
- ✓ The {EmailAccount} folder template reorganizes them into one folder per address, in a single pass
- ✓ Refine by domain—for example, {EmailAccount:*@yourcompany.com}
- ✓ Splitting a mixed Mimecast archive back into individual accounts is built into the same conversion—no separate tool required
Filter, Search, and Scale in a Single Pass
Mimecast conversion isn’t only a format swap. In the Enterprise edition, you can search and filter the mail as it converts, and run per-account conversions in parallel.
Search and filter as you convert
- ✓ Search email with familiar operators modeled on Gmail and Microsoft syntax—plus Boolean, proximity, and wildcards
- ✓ Match patterns with regular expressions (PCRE2)—phone numbers, account numbers, or project codes
- ✓ Search inside attachment contents, including files nested within attachments—a Word document inside a ZIP
- ✓ Convert only the messages that match—filtering runs in the same workflow, with no separate tool or second pass
Run conversions in parallel
- ✓ Split output into one PST per account, then process those sessions concurrently instead of one after another
- ✓ Configure up to 16 concurrent sessions, launched together with a single Run all
- ✓ Expect a substantial speedup on capable hardware—a fast multi-core CPU, ample memory, and an SSD
- ✓ Queue more sessions than run at once; the batch advances unattended as each slot frees
Search, filtering, and concurrent processing are available in the Aid4Mail Enterprise edition. Attachment-text search covers extractable content (no OCR; encrypted or password-protected files aren’t extracted). Conversion speed depends on your hardware, the source data, and how much the filter removes.
Business Impact & ROI
Turn awkward, multi-user Mimecast archives into per-account mailboxes, converted and migration-ready.
Turn a Mixed Archive Into Per-Account Mailboxes
Reorganize and convert in one workflow
- Native SJF and EJF reading—no manual unzip
- Split a mixed download into one folder per account
- One PST per mailbox, named by email address
- Strip journaling envelopes during conversion
Process Large Archives Unattended
Concurrent sessions, queued and automated
- Run up to 16 sessions concurrently
- Queue the whole batch with a single Run all
- Substantial speedup on capable hardware
- Migrate to Microsoft 365 or Google Workspace next
Eliminate Manual Unzipping
Read SJF and EJF natively instead of extracting terabytes of ZIPs by hand
Reorganize by Account
Split a mixed multi-user archive into per-custodian mailboxes in one pass
Scale With Concurrency
Run up to 16 sessions at once for faster, unattended batch conversion
Migrate Cleanly
De-journal and convert to PST for Microsoft 365 import or direct migration
Real-World Applications
See how migration teams, legal teams, and investigators use Mimecast conversion across matters.
Leaving Mimecast
- Convert SJF/EJF exports into usable PST or EML
- Split a multi-user archive into per-account mailboxes
- Strip journaling envelopes for clean messages
- Migrate to Microsoft 365 or Google Workspace
eDiscovery & Legal Review
- Produce per-account PSTs for review platforms
- Apply Bates, case, and custodian tokens during conversion
- Search email and attachment content before export
- Deduplicate with NOT Type:Duplicate
Corporate Investigations
- Reorganize a mixed archive by custodian
- Search inside attachments and nested files
- Isolate after-hours or weekend activity by time
- Keep an auditable, per-account output set
Compliance & Retention
- Move legacy Mimecast archives off the platform
- Scope collections with content and pattern filters
- De-journal for the original delivered message
- Output to the format your archive or review system needs
Technical Specifications
Built for professional conversion workflows—native Mimecast support is an Aid4Mail Enterprise feature.
Supported Source
- ✓ Mimecast SJF (Standard Journal Format)
- ✓ Mimecast EJF (Envelope Journal Format)
- ✓ Zipped EML archives
- ✓ FTP download or external-drive delivery
Editions & Access
- ✓ Aid4Mail Enterprise (native Mimecast)
- ✓ CLI automation & flexible deployment
- ✓ Split by account ({EmailAccount})
- ✓ Concurrent processing (up to 16 sessions)
Processing
- ✓ Native SJF/EJF reading (no unzip)
- ✓ Journaling-envelope removal
- ✓ Post-acquisition search & filtering
- ✓ Bates / case / custodian tokens
- ✓ Incremental processing
- ✓ Deduplication (NOT Type:Duplicate)
Output Formats
- ✓ PST (one per account)
- ✓ EML, MBOX
- ✓ Direct to live Microsoft 365 / Google Workspace
- ✓ PST for Microsoft 365 network upload
Native Mimecast processing, splitting by account, and multi-session conversion are Aid4Mail Enterprise features. The {EmailAccount} template is available in the Enterprise and Investigator editions. Direct migration to live Microsoft 365 or Google Workspace is recommended for small archives; for large archives, convert to PST or EML, verify the results, then migrate from those files.
Native Mimecast Conversion
SJF + EJF
Both formats, read natively
Per account
Split a mixed archive
Up to 16
Concurrent sessions
Enterprise
Aid4Mail edition
Implementation Best Practices
Recommended Settings
- → Split a mixed FTP download by account first, then convert the per-account folders
- → Turn on Remove journaling envelope when the archive was journaled
- → Use “Use FNV-1a signature” filenames to speed up large conversions
- → Optimize for speed before terabyte jobs—fast SSD, avoid NAS, and exclude work folders from anti-virus
- → Raise “Maximum sessions running concurrently” (up to 16) on capable hardware
Common Pitfalls to Avoid
- ✗ Don’t expect Converter or Investigator to read Mimecast natively—it requires Enterprise
- ✗ Don’t leave Strict behavior on without testing—off is often preferred for Mimecast, but verify sent-mail coverage and duplicates
- ✗ Don’t under-provision disk space—splitting decompresses the archive
- ✗ Don’t expect instant results—terabyte archives can take many hours
- ✗ Don’t oversubscribe sessions on light hardware—match the count to your machine
Convert Mimecast Archives Without the Manual Work
Native SJF and EJF processing, split by account, de-journaled, and converted to PST—unattended. Start your free trial today.