USB Device Recognized / Not Recognized based on shut-down method

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Salt123

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Jan 20, 2011
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3
Hello,

I have a PC which is having a lot of trouble recognizing a USB data acquisition device. Starting from a situation where the PC *does* recognize the device, here is the basic pattern:

1. PC shows device in Device Manager under "Data Acquisition Devices".

2. If the PC is power-cycled via the power plug itself, the device is no longer recognized under Device Manager ("Unknown Device").

3. If the PC is power-cycled via Start Menu --> Turn Off, same results as above, no longer recognized.

4. If the PC is power-cycled via Start Menu --> Restart, no problems, device recognized.

When the device is not recognized, unplugging and replugging the USB cable makes no difference to the situation. In order to correct the issue, I disable and then enable via Device Manager (which also involves a restart).

This pattern is extremely repeatable.

I am working with WinXP SP2, Pentium, 2.8 GHz, 504 MB RAM.

This PC was returned from a customer site - the PC and USB device are used in a machine my company manufactures. Apparently this issue just started happening one day. We want not only to correct the issue, but in fact to understand the root cause and ensure it will not happen again in the future.

Any suggestions would be greatly appreciated - thanks!
 
Joined
Apr 27, 2004
Messages
4,719
You could try reinstalling the usb drivers.
JohnWill has fix that is worth a try

Johnwill's solution

Create a file with NOTEPAD containing the following lines and save it as FIX.REG
-------------------------- Use text after this line --------------------------------
REGEDIT4

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\Environment]

"DEVMGR_SHOW_NONPRESENT_DEVICES"="1"
-------------------------- Use text before this line --------------------------------

Double click on FIX.REG and say yes to the Merge Into Registry question.

Unplug ALL USB devices.
Open Device Manager.
View, Show Hidden Devices.
Uninstall all devices under USB Controllers.
Uninstall all devices under Disk Drives that you know are not present.
Uninstall all devices under Storage Volumes. Say no to any reboot prompts until you are finished. Also, if a Storage Volume doesn't uninstall, ignore it and move to the next one.
If you have a yellow ? with unknown devices, uninstall all of the entries there as well.

When this is done, reboot TWICE.

Reconnect the USB devices and see if they're recognized properly.

NOTE: If you have a USB keyboard and/or mouse, you'll have to modify the instructions and leave enough parts for those to function. I don't have one yet, so I haven't had time to modify the instructions.
__________________
Microsoft MVP - Shell/User
 

Salt123

Thread Starter
Joined
Jan 20, 2011
Messages
3
Thanks for the quick reply! Before I do this, I have 2 questions:

1. If this works, what will this tell me regarding root cause?
2. Will doing this destroy any "evidence"?

(this is really important - I am tasked not with "fix it" but "know why it happened")

Thanks!
 

Salt123

Thread Starter
Joined
Jan 20, 2011
Messages
3
Update: Since root cause cannot be found in a timely fashion, I'm going to try to modify my application to force recognition at initialization - to ensure that the customer isn't going to feel the pain on any machines in the future. I'll post back when I've made some progress.
 
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