I've had a lot of problems with the game hanging (becomes unresponsive) when I hit end turn since 1.4, as have a lot of other people by the sound of it, roll on 1.5!
However I've generally been able to keep playing by loading an earlier save and doing something slightly different. This time when I hit end turn the game consistently becomes unresponsive. I'm not sure if it's the turn number 151 (is the game trying to do random events?) or because of the fact that the Magnar AI is casting the Spell of Making. I think the Spell should finish this turn but fail because I've captured all of Magnar's towers + the forge of the Overlord. (That should stop it, yes? I've never seen an explanation of how to stop the AI casting the Spell of Making.)
I'm using Primal Savage's XtraSavage difficulty mod and his AI mod.
(The file was too large so I deleted all the "Debug Message: UnzipHelper attempting to read file with uncompressed size of 12" messages)
Save game: https://www.dropbox.com/s/rld1x17kvxar3mp/165.EleSav
I did a test where I hit End Turn for a few turns from an earlier save game, so some things should definitely have been different, e.g. I didn't take Magnar's capital, I'm researching something different. Game crashes at the same point, when I hit End Turn on turn 151 with Magnar one turn away from casting the Spell of Making.
(Again, I deleted UnzipHelper messages)
Save game: https://www.dropbox.com/s/pus31smdfins0m6/test.EleSav