I have tried several new downloads of Switch OSX and Switch OSX Plus trial with the same result.
Using Express Scribe I use Recover File Menu item to reload a .dct file. I then use the Save As Menu item and name it "TestAudio" and put it on the desktop. I then drag it to Switch window, but when I try to play or "Switch" it gives me an error message ".dct file is corrupt".
If it is corrupt Express Scribe is corrupting it. You would think something this vanilla would have been debugged. 