WHQL

WHQL stands for Windows Hardware Quality Labs, a certification process from Microsoft used to test and sign device drivers to ensure compatibility with Windows. It is part of the Windows Hardware Certification Program and historically linked to the Windows Logo Program. The goal is to provide a trusted indication that a driver has been tested against Windows requirements and should install with minimal issues.

Manufacturers submit driver packages to Microsoft or to Microsoft-approved testing labs. The submitted driver is tested for compliance with Windows driver models, stability, and interoperability on supported Windows versions, using a test suite historically built around the Windows Hardware Lab Kit (HLK). If the driver passes all tests, Microsoft signs the package digitally, yielding a WHQL certification. Signed drivers may bear a WHQL logo in distribution channels, and Windows can install them with reduced user prompts, improving the user experience.

WHQL applies primarily to software drivers (kernel-mode and related) and certain class drivers; hardware devices may also indirectly qualify through their driver software. The program aims to reduce compatibility risk for Windows users and streamline driver distribution via Windows Update and installation flows.

Since its inception in the late 1990s, WHQL certification has evolved with Windows versions. The program is one element of Microsoft's broader driver certification strategy and is tied to the digital signing requirements for driver packages. The WHQL logo is sometimes confused with "Certified for Windows" programs; while the logo indicated tested compatibility, it does not guarantee absence of issues.