Re: Lot not saving to library

@KingBasieSims4 I am guessing that there is something in the Mods/CC that you removed that may be conflicting with your game. Maybe it is a conflict with the new patch? It could be a number of things. There can also be remnant items from the removed Mods/CC left in the game cache, which was the reason for deleting the localthumbnailcache.package. Also, the reason for the game repair is to have Origin replace any files that may be different than they should be or missing. 

If your game is lagging you can do several things to help it out:

• Play in offline mode
• Play in windowed mode
• Don't put your graphics settings in 'Game Options' up high - keep them more in the medium quality range
• Uncheck uncompressed sim textures, post processing effects in 'Game Options'
  [If you're on Mac, you can experiment with unchecking retina (doing this seems to have mixed results)]
• Make sure your computer and your graphics cards are updated
• Make sure your game is updated
• Don't store a lot of items in your library
• Clear your cache regularly
• Keep a limited number of game saves in your game
• Check if your computer's graphics are a bit taxed by the game
• Run a game repair occasionally
• Use caution in how much you add to your game, including how many Mods/CC, and make sure they are always up to date and comparable with the game's current version

If the problem re-occurs, or you are having quirky stuff start to pop up again, there is some great troubleshooting advice at this link. You may want to try the game reset next time. That's the next thing I was going to have you try: https://answers.ea.com/t5/Technical-Issues-PC/READ-FIRST-Troubleshooting-your-Game/m-p/3621199