USB device Unknown Device on Boot up

USB device Unknown Device on Boot up

Post by RG9taW5pY » Thu, 15 Sep 2005 16:33:06

I am an app developer working on a system that requires a USB memory stick to
be installed on the system at all times. The problem I am having is that with
a lot of the memory sticks we use they are not being recognised on the boot
up of the machine. They appear in the device manager as Unknown Device. The
sticks need to be removed and then plugged back in for them to be recognised
as Storage Devices.
I have tried using DevCon.exe to remove teh device and then rescan for them,
which works for recognised devices but not for an unknown device.
Is there anyway to do through the DDk and preferably any tools that could do
the job for me


1. Many USB Devices are "Unknown Device" in Device Manager

2. USB device suddenly becomes "unknown device"

hi guys,

today something strange happened to my 4port usb hub. after
soft-rebooting my system i wondered why my external drives and mouse
didn't work (all connected to my usb hub).
at closer look i found out that an "unknown device" is plugged into my
machine which happened to be the usb hub.

of course i tried unplugging and replugging it to other usb ports but no
effects at all - stll unknown.

so i googled and found out that some people have experienced similar
problems and solved it by uninstalling all usb devices from the device
manager, deleting an "infcache"-file and rebooting. (and yes, i did "set
devmgr_show_nonpresent_devices=1" and did remove the nonpresent devices).
no effect. windows boots, installs and detects all usb devices but the
hub still remains unknown.

the odd thing about that: it's not a hardware failure. the usb hub works
perfectly in knoppix or in the BIOS setup (tried it with an usb-keyboard).

furthermore all other usb devices do work on my usb ports and the usb
hub works great on other machines.

system recovery and safe mode have also no effects.

i'm really puzzled. any ideas?


PS: i've also tried several chords.

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