How MailRelic is tested

PST files created by Outlook

MailRelic was checked against a test archive written by Microsoft 365 Classic Outlook on Windows 11. The archive was built to cover what real mailboxes contain:

• plain-text and HTML messages, with inline images
• rich-text content in notes and contacts
• emails attached to other emails, two levels deep
• contacts, contact groups, calendar items (including recurring and all-day), tasks and notes
• folder and attachment names in several alphabets, including emoji
• a folder tree ten levels deep

Every item Outlook saved to the file was compared with what was put into it: subjects, bodies, senders and recipients, folders and attachments. Attachment contents were compared by SHA-256. MailRelic read every item correctly.

Exports opened in other mail programs

• EML files exported by MailRelic were opened in Classic Outlook. Names in other alphabets displayed correctly, HTML with inline images rendered, and an attachment saved from Outlook matched the original byte for byte.
• An MBOX file exported by MailRelic was imported into Thunderbird, and its HTML messages with inline images displayed correctly.

Large archives

The largest archive used in testing is a 10.7 GB PST (10,658,778,112 bytes) containing one million messages in 50 folders. MailRelic's export engine exported all one million messages to MBOX with no failures, and the count matched the contents of the file. In the Windows application, an export of the same archive was used to check that progress is shown and that an export can be cancelled and a new one started afterwards.

This archive was created for testing with a separate PST-writing tool, not by Outlook. It tests file size and number of items. It is not proof that every large PST opens, or that every feature a large archive created by Outlook can contain has been covered.

The original file is not changed

The SHA-256 of the test PST was recorded before testing and again after opening it, browsing, reading, searching, saving attachments and single messages, exporting the whole archive to EML, exporting to MBOX and extracting all attachments. The two values were identical. This was repeated on a physical Windows x64 computer with the release build.

Release 1.0.0 on Windows

• Installed and run on a physical x64 Windows computer: install, launch, uninstall and reinstall.
• The installer, the installed application and the uninstaller are digitally signed by Ante Tomić, with a timestamp. Signature verification reported no warnings and no errors.
• Microsoft Defender scanned the installer and the installed application and found nothing.
• A MailRelic Personal licence stayed active after restarting the application and after uninstalling and reinstalling it.

Network activity

During testing, MailRelic made no network connections while an archive was opened, browsed, read or searched. The only connection observed was to Lemon Squeezy's licence service, when a licence was activated. What that sends is listed on the privacy page.

Not supported in version 1.0.0

• ANSI PST files from Outlook 97 to 2002. MailRelic identifies them and says so.
• OST files.
• Repairing damaged PST files. MailRelic reports the problem and does not change the file.
• Export to MSG or PDF.
• macOS and Linux.