What is a DRV file?

DRV (Device Driver) files are Windows system files that provide a software interface between hardware devices and the operating system. Device drivers translate generic OS calls into hardware-specific commands that physical devices can execute. Without a driver, the operating system cannot communicate with printers, graphics cards, audio devices, network adapters, cameras, or any other peripheral.

DRV files can be either legacy 16-bit drivers (from Windows 3.x/9x era — now obsolete) or 32/64-bit kernel-mode and user-mode drivers in the Windows Driver Framework. The underlying format is the Portable Executable (PE) format, identical to .exe and .dll files, just with a different extension and loaded by the kernel rather than as a user application.

How to open DRV files

• Device Manager (devmgmt.msc, Windows) — View which driver file is associated with each hardware device; right-click → Properties → Driver → Driver Details
• Dependency Walker / Dependencies (Windows) — Inspect which DLLs and kernel modules a DRV file links against
• Sigcheck (Sysinternals) — Verify digital signature and version information
• WinDbg (Windows) — Microsoft’s kernel debugger for deep driver analysis
• Hex editor (HxD, 010 Editor) — Inspect raw binary contents

Technical specifications

Common legacy DRV files in Windows

Modern drivers predominantly use .sys extension in System32\drivers\ while .drv is more common for user-mode audio and multimedia components.

Common use cases

• Printer drivers: Communication between Windows and printer hardware (spooler subsystem loads .drv files for printers)
• Display drivers: User-mode portions of GPU drivers (the kernel component is .sys; the user-mode component is often .dll or .drv)
• Audio drivers: The Windows Audio Session API (WASAPI) interfaces with hardware through audio DRV files
• Legacy device support: 16-bit .drv files from DOS/Windows 3.x era that some older applications still reference
• Virtual devices: Software-only drivers that simulate hardware (virtual audio cables, virtual COM ports)

Driver installation and management

Windows uses INF (setup information) files to direct driver installation. Driver packages typically contain:

mydevice.inf     — Installation instructions
mydevice.sys     — Kernel-mode driver component
mydevice.drv     — User-mode driver component (if applicable)
mydevice.cat     — Security catalog with Microsoft's digital signature

The pnputil.exe command manages drivers from the command line:

REM List all installed drivers
pnputil /enum-drivers

REM Add a driver package
pnputil /add-driver mydevice.inf /install

REM Remove a driver package
pnputil /delete-driver oem5.inf /uninstall

Security considerations

DRV files with kernel-mode access have unrestricted access to system memory and hardware — a malicious or poorly written DRV file can crash the system (BSOD) or compromise it completely. Since Windows Vista 64-bit, all kernel-mode drivers must be digitally signed by a trusted certificate authority. Unsigned drivers require disabling Secure Boot or enabling test-signing mode (bcdedit /set testsigning on), which is a security risk on production systems.

Rootkits frequently use malicious kernel DRV/SYS files to hide processes, intercept system calls, and persist through reboots. Tools like Autoruns (Sysinternals) and Windows Defender Offline scan mode can detect and remove rootkit drivers.

Troubleshooting driver issues

REM Run Driver Verifier (stress-tests drivers — may cause BSOD)
verifier /standard /all

REM Roll back a driver in Device Manager
devmgmt.msc → Device → Properties → Driver → Roll Back Driver

REM Analyze BSOD minidump in WinDbg
!analyze -v
lmvm drivername