Lastexception & LastUIexception help!

I seem to have several of these popping up, most from when I played without mods and several last crash files from a corrupt save file I had a few months ago. I have started a new save file (still getting lastexception) and have, a week ago, installed MCC command center for the first time ever using mods and it had shown me 3 lastexceptions in the last 2 days. I read that these can be harmless but since I still don't know what corrupted my last save file that I had been playing for years, I'm worried something will happen to this one too. Prior to a week ago I had no mods or cc, now I have just MCC installed (it is upto date). Any ideas?