Cache files
Every so often I like to clear my sims 3 cache files. Is it safe to clear all the pictures in the featured items folder because it gets tons in it over time? Also is it safe clearing the files in the thumbnails folder and letting them regenerate? I notice they get large in size after awhile.
GreenOak1357 Yes, it's safe to delete everything in FeaturedItems and Thumbnails. FeaturedItems contains data related to the ads you might see for Store content if you don't disable that feature, so it does literally nothing (except take up space) unless you're shopping from within the game. Removing the Thumbnails folder is like deleting any other cache folder—you'll get some slower loading of images the next time you open the game, as the data is regenerated, but that's all.
Many of us block FeaturedItems entirely. There are two ways to do this, and you can try both. One is to deny Write permissions on the folder for everyone, so the game can't dump files in there. The settings are under Properties > Security.
I tried this but found it made the game hang when closing, so I use the other method, which is to create a text file with the same name. It can be almost empty; the point is to call it FeaturedItems and strip the .txt extension off of it, so it has exactly the same name as the folder would. The OS doesn't allow two files or folders with the same name in the same location, so the game can't create the folder at all.
The only problem with this method is it breaks things when I want to install new content through the launcher, but that's fine, I move the file out when I'm installing stuff, and delete the new FeaturedItems folder and put it back when I'm done.
The other option is to block Sims 3 entirely through your firewall, but this would also prevent you from using other online features. Maybe you don't mind though.