Just thought I would bump this again to see if anyone has come across anything that can help get answers to the above?
have the same problem with actual Version of Lightroom (5.6). Do you have a solution in the meantime?
I just posted a similar question since this thread is over a year old with no answers posted. I had to re-install my old LR4 program on an old laptop to run a photobooth/slideshow for my church Halloween party. This was a great feature to shoot tethered and in real time run a slide show. It takes so long to keep rebuilding previews when you have to restart the slideshow to add additional pictures that you cannot do it. Last night I tethered shot over 300 pictures in photobooth and in real time was showing a slide show on a big screen. Picture quality was great and was cycling the pictures at 2 seconds. Definitely not an upgrade when this option was taken away...