Disabling steam overlay fixed this for me, worth a try.
I noticed that after retraining my main character at an inn, all of my previous training has disappeared (e.g. Gerivard's Training, Granis' Training). Presumably this should not happen. You may also want to increase your attachment size as I cannot attach a 2MB save with a 500kB limit. P.S. there are also some random errors in my log that may be of interest. output_log.txt