Do all Wave files exhibit the same behavior in SF-9? It is rare, but I have encountered files with the <.wav> extension that were not the atypical uncompressed PCM Wave and required a rare codec. Otherwise, have you tried: - Dragging the file to the timeline?, - Exit SF-9, Restart the PC and try again. - Clearing the cache and resetting SF.
btw @David-Lay5409. I think you are due for an upgrade. The current version is Sound Forge 17.