Since Update, Game Won't Save - Due to Mods/ccEvery so often, we'll get a game patch just before a game, expansion pack or just because and will make game mods and custom content incompatible with the game and will no longer work with the game or cause issues with the game.
Try this if your game won't save:
1. Backup your Sims 4 folder to your desktop. *See note below*
C:\Users\<Username>\Documents\Electronic Arts\The Sims 4
Note: Making sure to back the Sims 4 folder ensures that nothing gets deleted. It will all be safe in the backup folder.2. Move the Mods folder to the desktop for testing purposes. As they may have been broken or become outdated with each new game patch. See post linked below for more information.
Custom Content and Mods (Install/Remove/Organize/Fix)
http://www.carls-sims-4-guide.com/forum/index.php?topic=23495.msg410220#msg4102203. Try to save your game. If it saves, this may mean there is a conflict with a piece of CC or a mod. See link above for help with fixing the problem.
If the game is still not saving, see this post linked below for more tips:
Game Won't Save (Tips)
http://www.carls-sims-4-guide.com/forum/index.php?topic=29326.msg464812#msg464812----------
Reference Link:
Sims 4 Failed to Save
http://answers.ea.com/t5/The-Sims-4/sims-4-failed-to-save/td-p/5821842Note: This post has been locked as it's for informational purposes.