Before you hand a mailbox to a lawyer or an eDiscovery vendor, open it yourself and look. An hour of private review can tell you what is actually in the file, how big the relevant part is, and what questions to ask before anyone starts billing.
Most people never do this. They download a Google Takeout export, see a single file of 20 or 40 GB, can't open it, and send the whole thing off. Then they find out what was inside from an invoice.
What eDiscovery vendors actually do
eDiscovery platforms such as Relativity, Everlaw, Casepoint and Reveal (which now owns Onna and Logikcull) are built for legal teams handling evidence. They collect data, process it, let reviewers tag and redact it, and produce it to the other side in a defensible way.
That work matters, and for a real lawsuit you will likely need it. But it starts with uploading your data to their cloud. Pricing in this industry is commonly tied to data volume, so a mailbox full of newsletters and receipts costs the same to process as one full of evidence.
Why review first
A quick look before handoff pays off in four ways:
- You know the scope. "About 3,000 emails with this company between 2022 and 2024" is a far better brief than "here's 40 GB, good luck."
- You spot sensitive material early. Messages with your lawyer, medical details, or other people's private information are better flagged before a third party sees them.
- You ask better questions. Your lawyer can decide what actually needs formal processing once you can describe what's there.
- You keep control. Nothing leaves your computer until you and your counsel decide it should.
One important rule: review, don't edit. Keep the original file exactly as you received it. If you're under a legal hold or a lawsuit is likely, deleting or changing messages can cause serious problems. Send your lawyer the original, and use your review only to understand it.
How to review an MBOX privately with readmbox
readmbox opens MBOX files in your browser without uploading them. There is no server to upload to: the file is read on your own machine. You can check this yourself by opening your browser's Network tab while a file loads and watching no mail leave.
- Get the MBOX file. For Gmail, use Google Takeout, select Mail, download, and unzip. Thunderbird and Apple Mail also store mail as MBOX.
- Make a copy. Work from a copy and put the original somewhere safe and untouched.
- Open readmbox.com in Chrome or Edge on a desktop computer and choose your .mbox file. Large files take a few minutes to index the first time, then open instantly.
- Filter. Search by sender or subject and narrow by date range. "Everything from one company in 2023" takes a couple of clicks.
- Read and note what matters. Write down senders, date ranges and subjects that are relevant, and anything that looks privileged or sensitive.
- Export a working summary if useful. A CSV list of the relevant messages (date, sender, subject) gives your lawyer a quick map. A PDF of a few key messages is easy to share in a first meeting.
Reading and filtering are free. Bulk export in every format (CSV, PDF, EML, split MBOX, and attachments as a ZIP) is a one-time $29 unlock, with no subscription.
What to look for
- Key people: who the relevant emails are with, and their addresses
- Date range: when the relevant conversations start and stop
- Rough volume: how many messages actually matter versus the total
- Privileged messages: anything with your lawyer or prepared for legal advice
- Sensitive content: health, financial or family details, and third parties' private information
- Attachments: contracts, invoices or files that may matter more than the emails themselves
- Gaps: periods that seem to be missing, which your lawyer should know about
Bring these notes to your first conversation with your lawyer or vendor. They turn a vague, expensive request into a specific one.
What readmbox is not
readmbox is a viewer, not an eDiscovery platform. It doesn't do legal holds, chain of custody, privilege logs, redaction or formal production. If your matter needs those, you still need a lawyer and likely a vendor.
What it does is let you see your own mail first, privately, before anyone else does. It works on desktop Chrome and Edge, not on phones. Note that the site itself uses Google Analytics, which is disclosed on the page; your mailbox never leaves your machine.
This article is general information, not legal advice. If litigation is involved, talk to your lawyer before you change, move or share anything.
Have an MBOX to check? Open it in readmbox and see what's inside before you send it anywhere.
