Several USB devices are suddenly "Unknown Device" in the Device Manager?

Question

My printer and external hard drive (both USB) now come up as "Unknown Device" in Device Manager. I have used them both for months in the past with no problem on my Windows XP machine. When I check "Properties" it says that "No drivers are installed for this device." I have tried turning the devices off, unplugging them and plugging them in again (in the USB ports both in front and in back of my computer), to no avail. A few more notes:
-I have uninstalled and reinstalled the printer software, and nothing changes.
-I started up the computer in safe mode, and both "Unknown Devices" still showed up in the Device Manger.
-The devices start up fine when plugged into my ohter computer, so I'm pretty certain that the problem is not with them.
-Several flash drives also are "Unknown" when plugged in. Oddly, I have one flash drive that is identified properly.
I've looked over many user groups and help files, and haven't seen anything like this. Can anyone help?

Answer 1

Go into the Device Manager and uninstall all the devices and reboot. It should redetect all of them.



If not, go into the Device manager and remove that all the devices in that section. This will clear all USB device information. Reboot and it will reload the USB ports. Then insert the devices and they should be redetected. (Sometimes that table that holds that information gets corrupted.)

Answer 2

That happened to me, too...not sure why. I have Vista though. Here's what I did and it worked:



Basically I saved all my important stuff onto recordable dvds just in case something screwy happened, then I put in my OS disc and actually upgraded vista to vista. It took forever but everything turned out okay, all my files intact and everything. I assume the recognition problem is somewhere in the core of the os installation. I'm not sure that xp will let you do an upgrade of itself...it probably will though. Good luck

Answer 3

Oh all you need to do is reinstall the cd that came with your device. Then it will be "knowned"

Answer 4

works on XP pc but not on other and I suppose other is Vista? i won't say another word