CAB (Windows cabinet)
Also known as: .cab file, cabinet file, how to open cab
A CAB (cabinet) is a compressed archive format Microsoft uses to package Windows installers, drivers, and update components. Windows opens .cab files natively in File Explorer, and tools like 7-Zip can extract them too.
- Microsoft cabinet format for installers and drivers
- Opens natively in Windows File Explorer
- Already compressed; extracting writes full-size files
What CAB files are for
The cabinet format bundles and compresses files for software installation — it is the format behind many Windows drivers, system updates, and setup packages. You rarely create one yourself; you mostly encounter .cab files inside installers or driver downloads.
Windows reads .cab natively: double-click one in File Explorer to browse it, or right-click and use Extract. 7-Zip and similar tools open them as well, and the `expand` command-line tool can extract their contents.
The storage angle
CAB files are already compressed, so extracting them writes larger, full-size copies to disk. Loose .cab files left over from driver or update downloads can usually be deleted once whatever they belonged to is installed.
Many .cab files inside the Windows folder, however, are part of the operating system or component store — leave those alone and use built-in tools like Disk Cleanup or Storage Sense rather than deleting them by hand.