I tried thee different versions of the drivers, the one that came on the CD, and two that I downloaded from Tascam.com. I can't get X3 to work with this interface. IN the Audio Devices (in X3 preferences),  "US-322/US-366 ch 1" is listed, but the check box is disabled.
 
Any ideas?
 
Thanks!
Mike

Hi Mike
 
Use the latest one on the website. Note you should be updating the interfaces firmware alongside it.
Did you reboot? You could try renaming AUD.INI to see if that works.
 
Unrelated but you should be able to update to Win 8.1 for free in the MS store.

I had to update the 366 firmware for it to work with the current drivers.

Thanks Alex and Anderton. I got it to work. I realized that my problem was caused by plugging the USB into a hub instead of into the computer. Plugging it into the computer and installing the latest driver from the site fixed the problem.