What is VxD?
Virtual Device Driver (VxD) is a Windows driver that enables Windows operating systems to perform functions that run in privileged CPU mode. These drivers enable system hardware to communicate with internal Windows functions at lower levels.
All hardware devices such as Direct Memory Access (DMA) device, disk controllers, serial and parallel ports, keyboard, and display, sound, and video controllers are controlled by VxD files. Each VxD file comprises a code that is a driver to make a specific device work. A Virtual Device Driver ensures that the state of the device it controls is tracked for applications that are accessing it and that the device remains in the required state whenever an application using it is launched.
Some VxDs are also used to manage installed software such as the MS-DOS device driver. Vmm32.vxd, Vredir.vxd, Wsock.vxd, Ntkern.vxd, and Cmos.vxd are some of the VxD files that you will find on your Windows systems.
Virtual Machine Monitor is a software layer that is used to virtualize your PC into a number of virtual machine environments. These virtual machines are used to run more than one copy of the same or different operating systems on your computer at the same time.
Virtual Machine Manager (VMM) is the operating system component that manages the virtual machines and memory of your computer. Your Windows operating system can access the services offered by VMM only by using the required VxD file.
Causes of Vxd Errors
Just like Dynamic Link Library (DLL) files, VxD errors are also quite common on Windows systems. Problems in VxD files can generate fatal and Windows exception errors, when you run various Windows applications, such as Internet Explorer (IE), Outlook Express and Microsoft Office. Let’s discuss some of the common causes of VxD errors.
Older Version of VxD
When the manufacturer of a hardware device on your system does not properly differentiate between Windows 95, 98, and Windows XP drivers, then your operating system may display the device as Unknown Device in the Device Manager.
Absence of Device ID
Each hardware device installed on your PC has a unique identifier that is used by the Plug and Play feature of your operating system. An identifier includes information such as the device ID, vendor ID and revision ID. If this identifier is missing, your XP system will not be able to recognize the device, and in turn, may list the device as unknown in the Device Manager. Faulty and malfunctioning hardware may also generate an unknown device error.
There are number of other causes that can lead to VxD errors on your system. Some of these causes are:
- Damaged and corrupt registry
- Conflict between real-mode and protected mode drivers
- Virus infestation or damage in the Win.com or Command.com files
- Conflict between physical input/output address or RAM
- Incorrect CMOS settings
- Problems with the Plug and Play feature
- Faulty cache or memory
- Malfunctioning motherboard
- Re-initialization of already loaded protected mode driver by the Systemm.ini file
Steps to Fix VxD Errors
On Windows ME and XP systems, you can review and determine the cause of most of the VxD errors by starting up your PC in Safe Mode—Press F8 at system startup and choose the appropriate option. In Safe mode, open Event Viewer using the Control Panel > Administrative Tools option. Event Viewer will provide you with a detailed report on the module that is causing the error. You can also use the msconfig utility to clean boot your PC to find out the program generating the VxD error.
VxD files enable interaction between system hardware and internal Windows operating systems at lower levels. Incompatible driver files, a damaged registry, and conflicts between hardware devices, and memory modules are some of the common reasons behind VxD errors. You can prevent these errors by keeping your PC up-to-date with the latest security updates and device drivers. You must also try to download and install a registry cleaner software to regularly scan the registry and remove all errors from it to prevent it from getting damaged.