[pchelpers] Dallas & Gerald -- fixing USB drives that don't work in one computer

Hi!

First, the workaround and the fix, then I'll explain the why.

Workaround: Move the USB device to another port, see if it starts working
again.  It may not, and/or the other port may have been corrupted the
same way already.

Fix: Remove the USB device. Open a CMD.EXE window. Paste the
following into the CMD window:

   set devmgr_show_nonpresent_devices=1
   set devmgr_show_details=1
   start devmgmt.msc

After Device Manager opens, click View, Show Hidden Devices. Look for
and remove all "Unknown device". Remove all devices with the yellow
mark which indicates that it is not working properly. if you have
"Other devices", all items under that are probably grayed out or have
the yellow mark. Look under "Universal Serial Bus Controllers" and
remove all grayed-out devices. If the device is a drive, look under
"Disk drives" and remove any which are grayed out. If the device is a
mouse or keyboard, look under "Human Interface Devices", "Keyboards",
and "Mice" and remove any items which are grayed-out.  Restart
computer and see if the device works.

The why:

USB devices have a problem that are not normally seen with other types
of devices.

When you install a USB device, it is only installed for THAT
ONE PORT. Thus, when you disconnect it and plug it into a different
port, the driver must be installed again. If the device is not a
drive, and if you are logged on as a restricted user or with Vista's
UAC, you may get an installation prompt. The result is that in a
corporate environment where computers are locked down, you should plug
the device into all ports and ensure that the driver is properly
configured on each USB port; that way it won't matter how the user
moves things around. For example, if you are connecting a serial port
emulator, a new serial port number will be assigned for each new USB
port that the device is plugged into; if your software works with one
serial port #, you'll have to manually change the port numbers on each
device to match what the software wants. Windows will complain about
the overlap, but it is not a problem since you'll only one of that
device plugged in at a time.

When you un-plug and re-plug a device, Windows deactivates and
reactivates the driver. Installing, deactivating, and reactivating
drivers for USB devices seems to be a relatively sensitive operation;
it can get corrupted, so that the device appears to not work properly
when you plug it in, yet it works fine in another computer and another
device of the same type works ok, and it usually works ok when moved
to another port.

-- 
Scott.




-- 
-------list-services-below-----------
Regards, John Durham (list moderator) <http://modecideas.com/contact.html?sig>
Freelists login at http://www.freelists.org/cgi-bin/lsg2.cgi
List archives at http://www.freelists.org/archives/pchelpers
PC-HELPERS list subscribe/unsub at http://modecideas.com/discuss.htm?sig
Latest news live feeds at http://modecideas.com/indexhomenews.htm?sig
Good advice is like good paint- it only works if applied.

Other related posts: