Windows Guest failing to find USB devices

[Trader_Horn]

I have VB 4.1.2 (Win 7 Host, XP Guest) with Extension pack & Guest Additions installed. UAC is set to Off and I can get no USB devices seen by VB at all. I
insert a device (the host sees all of these), clicking 'Add a new USB filter' just gives <No devices available>.
I get the same with Windows 2000. I do remember running an earlier version of VB hosted on XP and never having this problem.

The following lines are from the VBoxSVC file when VB is loaded:
USBLibInit: CreateFile failed winEr(31)
00:00:00.031 USBLibInit: USB Service not found
WARNING [COM]: aRC=E_FAIL (0x80004005) aIID={dab4a2b8-c735-4f08-94fc-9bec84182e2f} aComponent={Host} aText={Could not load the Host USB Proxy Service
(VERR_FILE_NOT_FOUND). The service might not be installed on the host computer} , preserve=true

[mpack]

Are you sure the extension pack is installed? The error message seems to imply otherwise. Can you show a picture of the File|Preferences|Extensions dialog panel?

You may also have problems if you did not have admin privileges when the VirtualBox software was installed.

[Trader_Horn]

I will try to add the image here, but am having problems with inserting it at present. When I right clicked the Extension Pack I never get the option to 'Run As Administrator' which usually appears with an installer application.[img]d:\vbforum.png[/img]

[mpack]

When I right clicked the Extension Pack I never get the option to 'Run As Administrator' which usually appears with an installer

Running in admin mode applies only to the main VirtualBox app. The extension pack is just a plugin for virtualbox, not an installer. The VirtualBox app itself takes care of "installing it". All you need do on a Win7 host is double click the extension pack file. Of course VirtualBox itself has to be installed first, otherwise Win7 has no app associated with the extpack file.

I will need to see that image before we continue down the yellow brick road. Edit the message and notice the "Upload attachment" tab below the text window. Use the browse button to select your image file, and remember to click"Add the file".

[Trader_Horn]

Image of requested Extension

VBforum.png (35.64 KiB) Viewed 2704 times

Apperars to have worked - thanks (The image insertion, I mean, as I still have the problem with no USB).

[mpack]

Hmm. Well, thanks for the picture, which proves that you do indeed have the extension pack installed.

Next thing I would try is reinstalling VirtualBox. In fact I would uninstall first to be sure I was starting from scratch. When reinstalling make sure you are running with full admin rights, and take your time on each of the early dialogs: do not stop it from installing anything it would install by default.

Remember that this also means you have re-install the extension pack too.

Preferably start by downloading the latest matching versions of VirtualBox and the extension pack from the downloads page.

A final possibility if that some other app has installed a USB filter driver. A VBox reinstall should give VBox the pole position and fix that problem too.

[Trader_Horn]

Success, Thank you. I installed 4.1.8 and the Extension Pack, reloaded Guest Additions and the USB devices are now visible in all VMs. No idea what was causing the original problem though.