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We have a kiosk that uses a bio scanner from m2sys (usb device). It scans your palm to recognize you. Every so often, maybe 1-3 times a day, the bio scanner will become an unknown device. We are unable to see any patterns or commonalities. When we unplug and plug it back in, it becomes available again.

We have custom software that uses the bio scanner's software to communicate with it. We've added a crap load of logging on everything but there doesn't seem to be any pattern of when the thing shuts off. We have these devices deployed to multiple locations (100+) and they are all seeing the issues but we can not reproduce it here, at the main office.

I've evaluated the software and I don't see anything. I'm thinking it's a driver or hardware issue (but we can't reproduce the issues here in the main office) or maybe environmental interference of some sort like from scan guns, automatic doors, microwaves or something else.

Any ideas would be welcome. I'm looking for possible causes of the usb device becoming unknown or ways to figure out what the cause is.

  • no other usb devices have this issue, only the scanner
  • We've contacted the manufacturer and they blame our software
  • We're getting help from Microsoft, but they haven't found anything
  • OS is embedded XP
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For me that sounds strongly like a hardware error that is connected to the environment. It could be anything. From temperature to humidity over to cosmic rays. If it really is a hardware error there are few things you can log on the PC. – Christopher Perrin Jul 11 '12 at 2:09
up vote 2 down vote accepted

This is almost always a hardware problem. If Windows finds the device ID, it will search a table of known drivers for device IDs supported, and bind the driver to the device. However, broken devices often fail to identify correctly.

It is possible that the device momentarily lost power and came up improperly, or that it is not receiving sufficient power (which can make the logic in it unstable and error-prone).

Try a different USB port and also try connecting it through a hub.

It may also be a driver bug (unlikely), or a hardware bug, or a USB hub issue (unlikely). Personally, I would press further on the device manufacturer.

Also verify what the device ID is in the properties panel when it is an unknown device. If it is right, you have a driver or OS issue. If it is wrong or unknown, it's almost certainly a hardware issue.

If you can't replicate the issue, I'd strongly suspect power issues. The USB hub would solve this, as it has a power insert.

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Thanks. We've thought about these things but nothing changed. The ID goes to all zeros. I've already suspected hardware but since we can't reproduce it here in our main office, we can't push the manufacturer, they just keep telling us it's our code. Any ideas on logging to prove it's a hardware issue? – ILovePaperTowels Jul 11 '12 at 15:17
Check what the device ID is when it's unknown. If it's wrong, the hardware is almost certainly giving the wrong device ID. – Falcon Momot Jul 12 '12 at 3:28
The device id is wrong. Also, the device doesn't come back when restarting the system, it has to be unplugged and then plugged back in before windows will see it again. We saw it happen here in the main office yesterday but still don't know why or how to reproduce it. With the help of Microsoft, the manufacturer is considering it's their fault. – ILovePaperTowels Jul 12 '12 at 14:54

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