This is a Microsoft Windows driver bug with some 64GB CF cards. Sonnet is working with Microsoft to resolve this issue. (64GB and 128GB CF cards work fine with Qio and Qio-CF in OS X.)
A partial list of cards Sonnet has tested:
Patriot Pro CF 266x 64GB/128GB card is recognized under Windows
Lexar Pro 1000x UDMA 7 64GB/128GB card reports itself as 32GB
SanDisk Extreme Pro UDMA 6 64GB/128GB card reports itself as 32GB
Your computer may not be fully supported by the Qio BIOS. If you boot with SxS cards inserted into the Qio, it forces allocation of the busses and memory space needed. Some computers will refuse to allocated bus space for later insertion unless two SxS cards are inserted before booting.
If you are having hot plug issues, not basic SxS functionality, you can use CFScan utility to force the Qio to "see" a newly inserted device.
