Transitions not working

I was using Premiere Elements 14 successfully for several years and recently the Cross dissolve and Fade to black transitions stopped working (possibly others as well). After trying to resolve this problem without success I decided to upgrade.

I re-installed Windows 10 completely and purchased and installed Premiere Elements 2019 and BOOM .... transitions will not work. I can drag and drop say, the cross dissolve transition onto the timeline over the split between any 2 clips and set the time, say 3 seconds and ensure that it is centered. It displays as an aqua box over the split but does absolutely nothing. If I scrub along the time-line over the transition it has no effect and if I export to MP4 there is no cross fade.

Any help would be appreciated.