Find duplicate emails across your files —automatically
Upload a Sent folder and an Inbox, or two overlapping archive exports. RedactBox spots the copies using each email's Message-ID header and gives you a wizard to review and remove them — without touching the copy you want to keep.
The problem with duplicate emails
A 10,000-email SAR export often contains 3,000 duplicates.
Duplicates inflate page counts, slow review, and raise export costs.
Fuzzy matching gets it wrong. RedactBox uses the Message-ID header — the RFC 2822 globally unique identifier — so when a Message-ID is present, detection is exact. Emails missing a Message-ID (rare — typically drafts or malformed messages) pass through unchecked.
How It Works
Upload
Upload any combination of .mbox, .pst, .eml, or .msg files into a project.
Scan
RedactBox groups copies by Message-ID as each file parses. A banner appears above your email list with the count, updated live.
Resolve
Open the wizard, pick a keep strategy (Smart pick, Keep newest, or Keep oldest), and the extras are trashed and excluded from export.
What you get
Built for the exact workflows records and compliance teams run every day:
Cross-file detection using the Message-ID header
Detection uses the RFC 2822 globally unique identifier, so when a Message-ID is present the match is exact.
Live banner count
The duplicates banner updates as each file finishes parsing, so you can start reviewing before the full upload is done.
Three keep strategies
Smart pick chooses the most complete copy automatically. Keep newest and Keep oldest give you direct control when you need it.
Three-step wizard
Scan results, then review groups, then confirm. Nothing is trashed without your explicit approval.
Inline quick-resolve
Resolve a duplicate straight from any email row — no need to open the full wizard for simple cases.
Preview any email inline
Open an email inline before deciding. See the body, headers, and attachments so you know which copy to keep.
Dismiss with Undo and Restore
Dismiss groups you don't want to touch. Undo reverses the last action, and Restore brings back anything you changed your mind on.
"Needs duplicate review" filter
A dedicated filter surfaces every email that still has an unresolved duplicate group, for targeted workflows.
Clean exports automatically
Resolved duplicates are excluded from ZIP, PDF, and bulk exports, so the recipient only ever sees the copy you chose to keep.
Re-emerged detection
Upload another file later with the same email and the group re-emerges for review — nothing is silently overwritten.
“Needs duplicate review” filter
Undo and Restore anywhere
Re-emerged flag on new uploads
Built for the teams doing this work
Education records, SAR/DSAR, and FOI teams lose hours chasing duplicates across overlapping archive exports.
Subject Access Requests (SARs & DSARs)
Process SAR responses without sending the same email three times to the requester. Clean exports that match what was actually communicated, not what's in your archive five times over.
Education records (SARs for students, staff, parents)
Education records teams handling SAR and FOI requests often pull email archives that overlap across Sent/Inbox, staff handovers, and department exports. RedactBox deduplicates them so students, parents, and staff receive a single clean response.
FOI responses
Clean FOI responses that reflect what was actually sent. Fewer pages, faster turnaround, lower cost.
Clean exports, every time
Try RedactBox free. No card required to start a project.