I have an Xpress 100 and an Xpress 512. Both behave as expected except for failing to control any connected luminaires.
Both devices are recognized by ShowXpress on the splash screen and start rapidly blinking their green PC Link lights when sending DMX commands. Both return to a slow blink when not sending any DMX commands while ShowXpress is open. The DMX bar graph indicates normal functioning.
I've attempted connecting a Chauvet SlimPAR 64 RGBA, an ETC Desire D40xt, and an Ovation p65UV. Only the ETC D40 responds at all, and it mostly strobes briefly in random colors before stopping responding altogether. Restarting gets me another 10-15 seconds of strobing on the D40. The D40 does not indicate a valid DMX connection.
I've swapped DMX cables, DMX interfaces, fixtures, and power supplies all without success. I directly connect both interfaces to the USB ports on the my laptop.
The Xpress 100 shows up in the device manager as not having a valid driver. When I download the drivers and tell Windows to search the folder, the install fails with the message "Windows was unable to install your USB serial port". The Xpress 512 shows up in the device manager normally.
I run ShowXpress v9.2.22 (64 bits) on a Lenovo ThinkPad T470s running Windows 10 Pro, OS version 1903.