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LZMA2 file format

.lzma · .lzma2  ·  compression (single file)  ·  introduced 2009 by Igor Pavlov

What is a LZMA2 file?

LZMA2 is the compressor inside 7z and xz, released in 2009 as an improved, parallel-friendly version of the original LZMA algorithm. End users rarely see a bare .lzma2 file — it is almost always inside a .xz or .7z container — but command-line tools like 7-Zip and xz-utils accept it directly.

Most readers reach this page after double-clicking a .lzma file and finding their operating system unsure what to do with it. The good news: LZMA2 is a well-understood format with mature tooling on every major platform. It is supported in one click by mainstream archivers on Windows, macOS, and Linux.

How to extract a LZMA2 file

Opening a .lzma file is straightforward on every modern operating system. The exact steps depend on which platform you are on:

On Windows

  1. Locate the .lzma file in File Explorer.
  2. Right-click the file. If you have 7-Zip installed, choose 7-Zip → Extract Here. On Windows 11 the built-in extractor handles ZIP, 7z, RAR and several other formats directly through Extract All…
  3. If prompted, pick a destination folder and click Extract.
  4. The extracted files appear in a folder next to the original archive.

On macOS

  1. Find the .lzma file in Finder.
  2. Install The Unarchiver from the Mac App Store, or Keka for both creating and extracting.
  3. Right-click the file → Open With → The Unarchiver (or just double-click after Unarchiver is set as the default).
  4. The extracted folder appears next to the archive.

On Linux

  1. Use your file manager: right-click the archive → Extract Here (file-roller on GNOME, Ark on KDE).
  2. On the command line, run one of: 
    7z x archive.lzma    # works for almost any format
  3. The files appear in the current directory.

How to create a LZMA2 file

To pack files into a .lzma archive, you typically need an archiver that supports writing this format. Not every tool can create every format — for example, only WinRAR can create real RAR files. The sidebar lists the software known to read and write LZMA2.

On the command line, the canonical create command is:

# Use 7-Zip, PeaZip, or the format's reference tool to create .lzma files.

If you regularly create archives at scale, a dedicated archive automation suite can wrap this command in scheduled jobs, integrity checks, and offsite replication.

Strengths

  • Excellent ratio
  • Parallel-friendly chunking

Weaknesses and limitations

  • Slow at high levels
  • High memory use

Typical use cases

  • Building block for .xz and .7z
  • Software distribution

Technical details

LZMA2 uses the LZMA2 algorithm and is identified on disk by the magic byte sequence 5D 00 00 / 18. The standard MIME type is application/x-lzma. The format is an open specification and is free for any use.

Frequently asked questions

Is LZMA2 safe to open?

Archive files are containers — they are only as safe as what they contain. A .lzma from a trusted source is fine; one received from a stranger can hold malicious executables, scripts, or files engineered to exploit bugs in your archiver. Always keep your archiver updated, and never run unknown executables that come out of an archive. A safe workflow is to extract into a sandbox and scan the contents before opening anything.

What is the maximum file size?

Modern implementations support archives in the multi-terabyte range. The practical limit is your filesystem (FAT32 caps at 4 GB; ext4, NTFS, APFS, and exFAT all comfortably handle multi-TB files).

Can I password-protect a LZMA2?

Some archivers can wrap LZMA2 files in an encrypted container, but the format itself does not always include built-in encryption. Check your archiver's documentation.

How does LZMA2 compare to other formats?

See our format comparison pages such as ZIP vs 7z, ZIP vs RAR, and tar.gz vs tar.xz for side-by-side feature tables.

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