I have over 2,000 pictures in my slideshow project in MEP 2013 Pro. If I attempt to change the picture transition manually for each picture, that works. If I change one transition, and then have it "apply to all following objects", the software crashes. Same as when I try to change the picture length (from 7 seconds to 5 seconds) globally.
All of this usually works fine when having a project with only a couple of hundred pictures, why would it crash with that many? Having to manually set the crossfade for over 2,000 pictures will take a long time...
BTW: my PC is a Dell XPS, with 8 co-processors and 16 GB of RAM running Windows 7 Pro... so "power" should not be an issue!