Getting stuck in build mode

@ChaplainMark51 

Are you on a Mac or PC?

If you have any mods move the mods folder to the desktop. Delete localthumbcache.package file in the game folder and fix the game in Origin.
Origin/Library -right click on TS4 - option "Repair game"
You have to wait until Origin will fix all packs, not only the base game.

If you don't have CC or mods delete this file and fix the game also. The game will create the same new file but without saved errors.
Turn on the game to create a new, empty mods folder. Check if a game is working now without mods.

Then copy from desktop your mods and CC and paste it in the new mods folder. First, paste script mods every time checking if the game is OK. Do the same with CC but if you have a lot of this, try the 50/50 method

If it does not work then try doing a factory reset as described in this post:
http://answers.ea.com/t5/The-Sims-4/FAQ-Troubleshooting-Steps-amp-Known-Issues/m-p/3621199

I don't work for EA