What is CAB format?

CAB (Cabinet File)

The CAB (Cabinet) file format is a compressed archive format developed by Microsoft, designed to bundle multiple files into a single, space-efficient package. It has been a core part of the Windows ecosystem since the early 1990s, most commonly used to distribute software installers, device drivers, and system update packages.

CAB files use LZX or Deflate compression algorithms to reduce file size while keeping extraction fast — a priority for Windows Setup and Windows Update, which rely on CAB archives to unpack system files quickly during installation. The format also supports splitting large archives across multiple CAB files, historically useful for distributing software on floppy disks or optical media with fixed capacity limits.

Beyond installers, CAB files are used internally by Windows for storing driver packages (INF-based driver bundles), font collections, and compressed help files. Windows itself includes built-in tools like expand.exe and makecab.exe for extracting and creating CAB archives from the command line, without needing third-party software.

While CAB is deeply tied to the Windows platform, it's not the most convenient format for everyday file sharing or cross-platform use, since dedicated extraction tools are less commonly available outside Windows. Formats like ZIP or 7Z offer broader compatibility for general-purpose archiving.

Overall, the CAB format remains an important part of the Windows software distribution and update infrastructure, even though it's rarely chosen by users for general-purpose file compression today.

What programs can open CAB format?

  • Windows Explorer
  • 7-Zip
  • WinRAR
  • PeaZip
  • IZArc
  • cabextract
  • expand.exe
  • makecab.exe

Use cases for CAB format?

  • Distributing Windows software installers
  • Packaging device driver files
  • Bundling files for Windows Update packages
  • Compressing font collections on Windows
  • Storing compressed Windows Help files
  • Splitting large installations across multiple archive parts
  • Reducing installer download size
  • Extracting system files during Windows Setup
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