All my saves are legendary besides the couple of saves after I researched everything. The problem for me was the 6 button and that huge number. After many restarts/crashes I had no problems after letting the last research run it's full course without the 6 button on in the trainer. I have used all other options with no problems, but I think that 6 option with that huge number really messes things up somehow when reading the files for save games. Someone else also stated this in the forums which worked quite well for me.
Open research, click on all research except for the last 2, ctrl-s, then ctrl-l and a lot will be researched in the same turn.