Support

We're here to help you get the most out of Mbox Viewer.

Contact Us

If you need help, have a question, or want to report a bug, email us at:

[email protected]

We typically respond within 24–48 hours.

Getting Started

  1. Download Mbox Viewer from the Mac App Store or from our website.
  2. Open the app and drag an MBOX or EML file onto the window, or use File → Open.
  3. The app will index the file on first open (this may take a few minutes for very large files).
  4. Browse, search, and export your emails — all processed locally on your Mac.

System Requirements

  • Operating System: macOS 14 Sonoma or later
  • Architecture: Universal Binary — Apple Silicon (M1/M2/M3/M4) and Intel
  • Storage: 30 MB for the app, plus space for index files
  • Supported formats: MBOX, EML

Frequently Asked Questions

What is an MBOX file?
MBOX is a standard format for storing email messages. Gmail's Google Takeout exports your emails as MBOX files. Many email clients and servers use this format for backups and archives.
Can it open very large files?
Yes. Mbox Viewer uses a streaming parser that never loads the entire file into memory. It can open files of 50 GB and beyond. The first open indexes the file, and all subsequent opens are instant.
Does it modify my MBOX file?
Never. Mbox Viewer is strictly read-only. It creates a small index file alongside your MBOX for fast access, but never writes to the original file.
What's the difference between Free and Pro?
Free includes all features but is limited to MBOX files up to 500 MB. Pro removes the file size limit. There's no feature gating — search, export, labels, threading all work in both versions.
What macOS versions are supported?
macOS 14 Sonoma and later. Universal Binary — runs natively on Apple Silicon (M1/M2/M3/M4) and Intel Macs.

Troubleshooting

The app takes a long time on first open

Mbox Viewer builds an index the first time you open a file. For large files (10+ GB), this may take several minutes. Subsequent opens will be instant (under 1 second).

My file doesn't open

Make sure your file has an .mbox or .eml extension. If the file is inside a ZIP archive, extract it first. If you still have issues, please contact us.

Search returns no results

Make sure the file has finished indexing (check the progress indicator). For body text searches, press Enter to trigger a full-text scan. See the search syntax reference for advanced queries.

See also: Privacy Policy · Terms of Service · Refund Policy