Ideas
Same thing happened to me yesterday. I was placing lots in Tomarang, 2 placed fine but when I went to place a 3rd one I got the infinite loading screen. It was over 1/2 hour before I finally decided to CTRL+ALT+Delete and shut it down.
I hadn't saved in a while so I was trying to avoid losing what I had done.
I have absolutely NO CC and NO MODs in my game. I always remove the game folder and put it on my desktop to create a new one whenever there's an update.
This is not a new save though, but it's a save that I started customizing the worlds a few weeks back, but it never had Mods or CC in it so I figured that save was fine since everything in it was just vanilla game items.
So I can assure you, this is not mod related. This is an issue with the game!
This is the 2nd play session I've had issues with since Lovestruck's update.