Tiff and PSD files no Longer show Transparency

[RaycerX]

I've rendered out with alpha channels two dozen or more times since starting to use Keyshot Pro and never had any issues. Now, I'm trying to render out some see-through acrylic panels (which I've done before), but when I open the PSD or Tiff file in Photoshop they're no longer transparent, but fully opaque. If I put something behind the panels it's not visible. There should be at least 90% visibility through the panels, but I'm getting a big fat zero percent. Any idea what could be wrong. Is there a setting I left on or off that could be the issue? Thanks.