How to remove non-present devices from virtual or physical machine

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These days system virtualization is used almost everywhere. Most of you who are reading this article have probably already used some of the well known virtualization applications like Virtual PC, Hyper-V, Xen Server, VmWare ESX or VmWare workstation etc. I will give you a tip on how to improve your virtual machine performance, especially if you've made a physical to virtual conversion.

For instance, you've connected some devices to your PC, which you won't use anymore. The device is removed but the driver stays for good.

Those 'left-over' drivers can cause problems if they become enabled in the means of hardware conflicts or system starts to behave strangely.

Here is the tutorial on how to remove those drivers.

For a start we have to add environment variable:


Open in new window

To the Environment Variables dialog box.

Right click 'My Computer' | Properties | Advanced System Settings | Environment Variables'

Click NEW under 'System Variables' and add 'devmgr_show_nonpresent_devices' environment variable to the System Variables panel.

When the dialog box appears type 'devmgr_show_nonpresent_devices' in the Variable Name field and type '1' in the Variable Value field.

Hit OK.

Now to remove 'non-present devices' in device manager.

Hit 'Windows Orb' and type 'Device Manager'

When Device Manager opens, select the 'view' menu and choose 'Show Hidden Devices'. Open any of the hardware selections, for instance 'Disk Drives'

Here you can see greyed device drivers which aren't currently in use. If you are sure that you won't need those drivers anymore, right click on it and click uninstall.

This procedure will rapidly reduce the time required to boot your OS. We have tested it on Windows Server 2003 and Windows Server 2008 virtual machines.

If you need help, please post a comment and I will try to help.

I've posted this article on my site:

Hopefully, you'll find it useful.

Expert Comment

a good article

i would suggest to do the followng to be faster
open command prompt (cmd)


Expert Comment

Very useful thanks

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