VISA doesn't find my USBTMC

[porpoisewise]

I have a USBTMC device. When I try to connect  the USBTMC device, It give me an error message.

return value : BFFF003E

status name : VI_ERROR_IO

 I can see the USB Device in MAX , but  it's show "Unknown".

The USB driver is NIUSBTMC.SYS .

I have checked the interface Descriptor. Could you help me solve the problem?

[Makoto]

What USB instrument are you using? And is it truely USBTMC compliant?

[JoshuaP]

Also make sure you are using NI-VISA. If you have installed any other VISA on your system like Agilent VISA it will not work. You will need to uninstall the other 3rd party VISA.

-Josh