32bit float files not opening

I just purchased a Sound Devices MixPre-6 II and made a couple of test 2-channel recordings at 32bit float, 96khz. When I drag them both into the file group window, I see an empty waveform with a red overlay and the message “The file cannot be found”. If I try dragging them in individually or open them from the file dialog, nothing happens. What am I doing wrong?

This is using Wavelab 9.5 on Windows 10.