The game failed to save. Error code: 510:78f70847:44708b40

@Sfe32ygz3

Try to remove them and see if the game works better.
For example, move the mods folder from C:\Users\Username\Documents\Electronic Arts\The Sims 4 to your Desktop and start the game.

If that works but you want to keep your mods, you can try some different things to sort out the ones not working:

• If your problem occurred after a certain mod haul, remove all these new mods (see if the game works), and then add back a few at a time, restarting the game in between until you see the problem occurring again. Remember that you can possible have several broken mods.
• If the problem started after the latest patch/update, always make sure to update your mods when you update your game. Check this list out for some mods that were broken in the C&D-patch! A few others have been broken after but not so many that there is a list.
  http://forums.thesims.com/en_US/discussion/928106/broken-mods-cats-and-dogs-nov-2017
• Download Sims 4 Studio and do batch-fixes for your cc.
• Search for the Mod Conflict Detector on google and run it, see if it can detect some broken/conflicting mods, remove these and try your game again. (Only detects conflicts between mods, not between mods and the game)
• Like the first "solution", but for all your mods. Remove all and put back some at a time to find broken ones (last resort if you have like 1000 mods).

Good Luck!