RIGblaster plug & play needs USB-2

Tried to communicate with a RIGblaster plug & play via Java RXTX.
The Rigblaster is essentially a USB-to-serial converter. All functioned fine on a new Windows 7 computer with 64 bit Java, until suddenly it didn't. The RXTX code hung somewhere in its CommPortIdentifier class that is used to open a port.

Reason turned out the type of USB port. This computer happens to have USB-2 as well as newer USB-3 ports. With USB-2 all is fine, with USB-3 the RXTX library hangs.