How do I transfer Sims 3&4 files to a new computer?

Download and install the games on you new computer.

Start each game and allow it to load to the main menu then, exit the game, no need to save. This will create all of the required folders in Documents.

Copy your saved files into the corresponding (same) folder on the new computer. Allow Windows to merge those folders if it asks, if it asks to replace a file, choose NO - those are files created by the game with information specific to the hardware in the new computer.

Launch your game. You should have all of your stuff from the old computer now.

Is it only the ones in Documents that I need to copy over. Or are there others?

Just the ones in Documents, those are your user files for each game. The stuff in other places is put there during install or automatically when you run the game.

Thanks a bunch! Once I figured out where all my saved files where on my backup, I was able to transfer everything over. :D

I transferred the files, I put the save folders from my old computer in the new save folder. But I can't access them in game. I tried removing the files themselves, and putting them in the new save folder by themselves, and that didn't work either.

@LBonne24

Are you sure that you added the save files to C:\Users\yourname\Documents\Electronic Arts\ Sims (3 of 4)?

I did, I added the ones from the save folders under Sims 3 and Sims 4

@LBonne24

I am not sure why your game is not picking up the save files then. Bad news: we are unable to restore lost save files for you ☹️

I will move this thread to the Sims 4 forums for you - perhaps some of our regular Sims players have more insight into this for you.

Make sure you run the game at least once before copying over the data. 

You can either overwrite of copy the files the over. 

If you want to read more about back ups:
http://sims4.crinrict.com/en/2014/09/backups/
http://sims3.crinrict.com/en/2011/03/faq-what-files-should-i-backup.html

Do I need to bring the saved outfits over too? Should I just copy the whole Sims 3 folder and put it in the new saves folder?