How to Search MBOX File Data on Windows and Mac

Why Search MBOX Files?

MBOX archives grow for years and four needs make a search tool valuable.

• Audit and Legal Requests. Auditors and lawyers ask for emails from one sender or inside one date range.
• Finance Records. Accounts teams look for an invoice or a purchase order in an old mailbox backup.
• Missing Attachments. You remember the name of a PDF and need the email that came with it.
• Migration Checks. A few known emails show you whether your data arrived in the new mailbox.

What Makes Searching Inside an MBOX File Hard?

MBOX saves a mailbox folder as one text file and stores every email after the one before it. Text editors open the file but cannot filter emails by sender or date.

Email text and attachments also sit in encoded form. RFC 2045 on MIME encodings defines base64 for binary data and quoted printable for mostly text data.

Base64 replaces readable text with random looking characters and a typed keyword never matches it. Quoted printable splits long lines and replaces non ASCII characters with codes. Our What is MBOX File guide explains the format basics.

How to Locate the MBOX File You Want to Search?

Locate the file before you open it.

• Thunderbird on Windows. Type %APPDATA%\Thunderbird\Profiles in the File Explorer address bar and select your profile folder.
• Thunderbird on Mac. Open ~/Library/Thunderbird/Profiles in Finder with Go > Go to Folder.
• Thunderbird on Linux. Open ~/.thunderbird and select your profile folder.
• Apple Mail. Select a mailbox and choose Mailbox > Export Mailbox to create an MBOX file.
• Google Takeout. Extract the Takeout download and find the file with the .mbox extension.

What to Check Before You Start?

Prepare the file before you search.

• Copy the MBOX file to a backup folder before you import or open it.
• Quit your email client before you copy a mailbox file from its folder.
• Note the keyword, the sender address and the date range you need.
• Check the file extension because MBOX, MBS and MBX files open in the viewer software.

Which Free Methods Find Emails in MBOX Files?

Three free methods exist. Thunderbird and Apple Mail import the file first and the command line scans the raw text.

Thunderbird (Free, Needs an Import)

Thunderbird searches the messages in folders you add. Import the MBOX file before you search.

1. Import the MBOX file into Local Folders. Our Split MBOX File guide shows the Thunderbird steps.
2. Select the new folder in the folder pane.
3. Press Ctrl + Shift + K on Windows or Command + Shift + K on Mac to open the Quick Filter bar. Quick Filter narrows the messages in the current view.
4. Type your keyword in the Quick Filter bar.
5. Press Ctrl + K or Command + K to use Global Search. Global Search looks through all messages.
6. Press Ctrl + Shift + F or Command + Shift + F to open the Search Messages dialog and search one folder.

Thunderbird lists these shortcuts in Mozilla keyboard shortcuts for searching. Large MBOX files take longer to import and you repeat the import for every file.

Apple Mail (Free, for Mac)

Apple Mail imports MBOX files into a new mailbox and then searches the emails in it.

1. Click File in the Mail menu bar and select Import Mailboxes.
2. Choose Files in mbox format as the source and click Continue.
3. Select the folder that has your MBOX file. Mail adds the emails to a new mailbox named Import in the sidebar.
4. Select the Import mailbox. Click the Search button in the toolbar when the search field is hidden.
5. Type your keyword and select a suggestion from a category like Subject or Attachments. Mail turns the suggestion into a search filter.
6. Add more filters to narrow the results. Mail shows only the emails that match all filters.
7. Type from: and a sender name to search by sender. Use uppercase AND, OR and NOT between terms.
8. Click Search all mailboxes when the Import mailbox shows no matches. Mail then searches your other mailboxes too.

Find the full import steps in our Import and Export MBOX in Apple Mail guide. Apple explains the search filters in Search for emails in Mail on Mac.

Command Line (Free, Raw Text Only)

Windows PowerShell and Mac Terminal scan an MBOX file as plain text and need no import.

1. Open PowerShell on Windows or Terminal on Mac and Linux.
2. Use the cd command to go to the folder with your MBOX file.
3. Type the command below on Windows. Matches ignore letter case by default.

Select-String -Path .\Inbox.mbox -Pattern "invoice"

4. Type the command below on Mac and Linux. Option i ignores letter case.

grep -i "invoice" Inbox.mbox

5. Replace Inbox.mbox with your file name and invoice with your keyword.
6. Add -Context 2,3 to Select-String to show 2 lines before and 3 lines after every match. Add -n to grep to show line numbers.

Microsoft lists every option in Select-String documentation.

How to Search MBOX Files With EmailDoctor Software?

EmailDoctor MBOX Viewer Pro views MBOX, MBS and MBX files with no email client and searches mail fields and attachments in one file or many files. Search belongs to the Pro edition and the free viewer edition previews emails and attachments only.

Windows 11, 10, 8 and 7 support the software and so do Windows Server 2019, 2016, 2012 R2 and 2008. Right click the shortcut and select Run as Administrator before you start.

Six features narrow a search.

• Keyword Box. Type a word and select the OR, AND or NONE operator beside it.
• Header Fields. Type text in the To, Cc, Bcc and Subject boxes to search one field.
• Mail Criteria. Add Body, Received Date, Sender Name, Sent Date, Modification Date, MD5, From and Message Header filters.
• Attachment Criteria. Filter attachments by Extension or Name.
• Look For. Limit a search to mail or attachments.
• Saved Scans and Results. Save a scan or a search result and reopen it later.

Search Emails in an MBOX File on Windows

1. Start the software. Right click the shortcut and select Run as Administrator.
2. Click Add File in the toolbar.
3. Select File to add one MBOX file or Folder to add many files. Click ... next to the path box and select your MBOX file. Click Open.
4. Click Add to list the file in the software.
5. Let the scan finish and check the file location, size and time stamp on screen. Click Yes when the software asks you to save the scan file.
6. Select the file and check your emails in Normal Mail View.
7. Click Search at the bottom of the left pane. Type your keyword in the search box and select AND, OR or NONE as the operator. Type text in the To, Cc, Bcc or Subject box to search one field.
8. Click Add Criteria > Mail and select a field like Body, Sender Name or Sent Date.
9. Click Add Criteria > Attachment and select Extension or Name.
10. Click Look For to search mail or attachments. Click the search icon beside the keyword box.
11. Select a result to open it in views like Normal Mail View, Message Header or Attachments. Use the icons above the search box to save, reopen or clear a search result.
12. Click Export and select PDF or Print to save or print the emails you need.

    Search one keyword in a small file first and compare the result count with Thunderbird or Apple Mail.

    Viewer software works on Windows only and Mac users follow the Apple Mail method above. Pro+ edition adds PST, EML and MSG export. Need the attachment files themselves? Follow our Extract Attachments From MBOX File guide.

Which Method Suits Your MBOX File?

All four methods find emails in an MBOX file but they differ in results and platforms.

Thunderbird or Apple Mail suits a few emails and a command line suits a quick check of one keyword. Viewer software suits many files, attachment searches and repeat searches.

What Problems Appear During an MBOX Search?

Six problems slow an MBOX search.

• Keyword Finds Nothing in the Command Line. Base64 text never matches a typed keyword so a search for the sender address works better.
• Quick Filter Shows Fewer Emails. Quick Filter works on the current view and Global Search with Ctrl + K searches every message.
• Apple Mail Shows Other Mailboxes. Select the Import mailbox in the sidebar before you search and avoid Search all mailboxes.
• Search Option Missing in the Viewer. Search belongs to the Pro edition and the free viewer edition has no search.
• Software Does Not Start. Right click the shortcut and select Run as Administrator.
• Large File Searches Slowly. Split the file into smaller MBOX files with our Split MBOX File guide and search every file.

Frequently Asked Questions

Final Words

People search MBOX file data to find one email in a plain text file with no search tool. Thunderbird and Apple Mail search after an import and a command line searches raw text only.

Back up the file and test one keyword on a small file first. Compare the result count with a second method before you trust the result.

EmailDoctor software finds emails and attachments across many files and saves scans for repeat searches.