Extract text from Firefox profile files (MOZLZ4)
To convert MOZLZ4 profile files to another format, you need Mozilla Firefox or other Compressed software.
To convert other file formats to the "Mozilla Profile Data" file type, you need software like Mozilla Firefox or a similar tool.
The .mozlz4 file type is a proprietary compressed container used exclusively by Mozilla Firefox and related browsers (like Thunderbird) to store sensitive profile data. Common examples include search.json.mozlz4 (search engine configurations) and extensions.json.mozlz4 (add-on settings). While the underlying data is standard JSON text and the compression algorithm is standard LZ4, Mozilla wraps these files with a non-standard 8-byte "magic header" (mozLz40\0) and a 4-byte size declaration.
This custom header is a major limitation for users. Standard decompression tools like 7-Zip, WinRAR, or even the official LZ4 command-line utilities cannot recognize or open these files - they will report the file as corrupt or unknown. Consequently, users cannot simply open a .mozlz4 file in a text editor like Notepad++ to recover a lost session or edit search providers. To access the data, the file must be converted (decompressed) to JSON or TXT by stripping the proprietary header and processing the LZ4 stream. For users intending to edit and restore the file to Firefox, it must be re-compressed with the exact same non-standard header, or the browser will reset the file to defaults.
Convert.Guru analyzes your MOZLZ4 file, detects the exact format, and lets you read the text inside.
Users also converted LZ4, JSM, MAFF and XUL files.
If you want to convert MOZLZ4 file to , you can use Mozilla Firefox or similar software from the "Browser Configuration Storage" category. In the File menu, look for Save As… or Export….
To convert files to MOZLZ4, try Mozilla Firefox or another comparable tool in the "Browser Configuration Storage" category.
The history of Convert.Guru began over 25 years ago in California with Tom Simondi’s file-format database. A former contributor to Space Shuttle development and a software pioneer of the 1980s, Simondi established a trusted resource for file type analysis that was even referenced by Microsoft Windows XP. Today, we use modern technology to process and convert thousands of file formats while continually improving our MOZLZ4 converter.