Email Search Tool for Lawyers and Legal Investigation

A litigation hold just landed on your desk. You need to find every email mentioning a specific contract clause, sent between two dates, across 40 GB of PST and MBOX archives. Enterprise eDiscovery platforms handle this — at $2,000 to $10,000+ per year. Mail Terrier does the same keyword search across email archives for a one-time $199 commercial license. Free for personal home use. Here is what it offers:

• Searches PST, OST, EML, MSG, MBOX, and EMLX files stored on your hard drive
• Advanced query rules: AND, OR, NOT operators, proximity search, date range filtering
• Filter by sender, recipient, subject, or attachment name
• Exports matching emails to PDF, XLS, DOC, TIFF, EML, or MSG
• Runs 100% offline — no client data leaves your machine
• Processes thousands of emails in minutes, not hours

Download Mail Terrier and run your first legal email search in under five minutes.

 

Why Lawyers Need Email Search Tools

Email is the primary evidence source in modern litigation. Courts expect parties to produce relevant electronic communications quickly and completely. This obligation — known as eDiscovery — applies to lawsuits, regulatory investigations, internal HR matters, and compliance audits.

The challenge is scale. A single employee generates thousands of emails per year. When a legal matter involves multiple custodians across several years, you are looking at tens of thousands of messages spread across PST exports, MBOX backups, and loose EML files. Manually reading through these is not feasible. You need a search tool that can scan all of them by keyword, date, and participant — then export the hits in a format you can attach to a court filing or share with opposing counsel.

Enterprise eDiscovery platforms (Relativity, Nuix, Everlaw) solve this problem at scale, but they are built for large law firms and corporate legal departments. Licensing starts at thousands of dollars per year, often per-seat. Solo practitioners, small firms, paralegals, and in-house compliance teams frequently need the same search capability without the enterprise price tag.

Mail Terrier fills this gap. It searches local email archives by keyword with Boolean logic, date ranges, and sender/recipient filters. It exports results to PDF and Excel for court submissions. And it costs $199 once — no subscription, no per-seat fees, no cloud dependency.

How to Search Email Archives for Legal Cases

• Step 1. Launch Mail Terrier and point it to the folder containing your email files. It reads PST, OST, EML, MSG, MBOX, and EMLX directly from disk — no Outlook or Thunderbird installation required.
• Step 2. Enter your search keywords. Use Boolean operators (AND, OR, NOT) to build precise queries. Example: "settlement agreement" AND NOT "draft" finds emails discussing the final agreement while excluding drafts.
• Step 3. Set date range filters to narrow results to the relevant time period. Add sender or recipient filters if you know which custodians are involved.
• Step 4. Click Search. Mail Terrier scans all selected email files and displays matching messages with sender, date, subject, and a content preview.
• Step 5. Review the results. Select the emails you need and export them to PDF for court filings, XLS for spreadsheet review, or EML/MSG to preserve them as standalone email files.

The entire process takes minutes, even on archives with tens of thousands of emails. Each search is logged, so you can demonstrate to the court exactly what terms were used and when the search was performed.

Mail Terrier vs Enterprise eDiscovery Software

Feature	Enterprise eDiscovery	Mail Terrier
Price	$2,000–$10,000+/year	$199 one-time
Email formats	Varies by platform	PST, OST, EML, MSG, MBOX, EMLX
Boolean search	Yes	Yes (AND, OR, NOT, proximity)
Date/sender filtering	Yes	Yes
Export formats	Platform-dependent	PDF, XLS, DOC, TIFF, EML, MSG
Cloud dependency	Usually cloud-hosted	100% local, no internet needed
Setup time	Days to weeks	Install and search in 5 minutes
Per-seat licensing	Yes	No — one license, one price
Training required	Extensive	Minimal — familiar search interface

Windows 7/8/10/11 • 30-day free trial

Key Features for Legal Professionals

Advanced Search Rules

Mail Terrier supports AND, OR, and NOT operators, phrase matching with quotes, and proximity search to find words appearing near each other. You can combine multiple conditions in a single query. This level of search logic matches what enterprise eDiscovery tools offer for keyword searches.

Export to Court-Ready Formats

Matching emails export to PDF with full headers (sender, recipient, date, subject) intact. PDF output is suitable for court filings, exhibits, and document production. XLS export creates a spreadsheet index of all matching emails — useful for privilege logs and review tracking.

Multi-Format Email Support

Legal matters rarely involve a single email format. A departing employee might have a PST from Outlook, an MBOX from a personal Gmail backup, and loose EML files from a webmail download. Mail Terrier searches all six major formats in the same session without conversion.

Search History and Reproducibility

Every search you run is logged with the exact query, date range, and filters used. If opposing counsel or the court challenges your search methodology, you have a record showing precisely how you found the produced documents.

No Cloud, No Data Leaks

Mail Terrier runs entirely on your local Windows machine. Email data never leaves your hard drive. This eliminates confidentiality concerns that come with uploading client communications to cloud-based eDiscovery platforms. Attorney-client privilege stays intact because the data stays on premises.

Litigation discovery. Opposing counsel requests all emails between two parties discussing a specific contract term during 2021–2023. You point Mail Terrier at the custodian's PST exports, search for the contract term with a date range filter, and export the results to PDF. What would take days of manual review is done in an afternoon.

HR investigation. An employee files a harassment complaint referencing specific email exchanges. HR needs to search the accused employee's mailbox for corroborating messages. Mail Terrier scans the PST or OST file by keyword and sender, producing a clear set of relevant emails without involving IT or exposing the investigation to more people than necessary.

Compliance audit. Financial regulations require firms to retain and search communications related to specific transactions. When auditors ask for emails mentioning a deal name or client during a particular quarter, Mail Terrier finds them across all archived mailboxes and exports the results to Excel for a structured review log.

Regulatory response. A government agency issues an information request covering email communications over a multi-year period. You need to identify responsive documents fast. Mail Terrier searches across PST, MBOX, and EML files from multiple custodians simultaneously, filtering by date range and keywords specified in the request.

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Mail Terrier Customer Reviews 2026

Rate ItRated 4.9/5 based on customer reviews

"I handle employment disputes for a small firm. We needed to search a former employee's PST file for emails related to a non-compete clause. Mail Terrier found 47 relevant messages in under two minutes using a Boolean query. Exported them to PDF, attached them to our motion. The tool paid for itself on the first case."

Catherine Marsh Litigation Attorney

"Our firm used to outsource eDiscovery searches at $300 per hour. Now I run them myself with Mail Terrier. I searched 12 GB of mixed PST and MBOX files from three custodians, filtered by date range and sender, and exported the results to Excel for privilege review. The attorney was surprised how fast it was."

James Orellana Senior Paralegal

"We archive departing employees' mailboxes as PST files. When regulators asked for all communications related to a specific transaction over a two-year period, Mail Terrier searched six PST archives and produced a clean PDF report. No cloud upload, no third-party access to confidential data. Exactly what we needed."

Helen Roe Compliance Officer

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