Installing TS4 on new PC - what can go wrong?

I recommend making a backup of the folders Saves, Screenshots and Tray. You'll find them under Documents/Electronic Arts/The Sims 4. Installing the game and then moving those folders into the new Sims folder should do the trick. A while ago, my computer crashed and needed a complete re-install, and if those folders hadn't been copied to both an external drive and OneDrive before the crash, I would have lost everything. Say what you will about OneDrive, but in this case it was a lifesaver. All I had to do after reinstalling the game was activate OneDrive and let it do its thing. It automatically downloaded all the files into the new Sims 4 folder, and at least my main save was still there. A few of my older households don't show up in the library any longer, though. No idea why that is, I think I might have overwritten them at some point.

Thanks. I always back up my entire ts4 folder to a portable drive. That said, it's probably smarter saving it far away physically. I keep it in a different room, and well, if everything I own is gone in a fire, I guess I will need to focus on a lot of stuff other than my game anyway.

I forgot about my library, but assuming that is included in the grand the sims 4 folder?

I'm not sure about the library; I only realised it was a bit of a mess after I reinstalled the game and checked to see if my main save was still working, and since it did, I wasn't too concerned about the missing old households, and I hadn't played much with them anyway because until I created my current main household, I never stuck with a household for longer than maybe two gaming sessions. Two of my current households are no longer in the library as well, but in the save. No idea how that's possible; maybe because the save was, well, saved after the crash. 

I was just thinking... Maybe you could upload the households and builds you want to keep to your gallery so you can redownload them later.

Simmerville  The data for your in-game library files is saved to the Tray folder, inside Documents > Electronic Arts > The Sims 4.  This Sims 4 folder holds all user data, basically everything aside from what the EA App installs.  Here's a description of everything in the user folder:

https://sims4.crinrict.com/eng/2014/09/user-files-explained/

None of the contents of this folder will transfer to your new computer unless you do it yourself, or unless you involve OneDrive in the process.  I wouldn't suggest that though because OneDrive has been known to eat saves and other user data for no apparent reason.  You can still manually upload to OneDrive, or any other cloud storage service.

I would suggest zipping the Sims 4 folder, or its subfolders, before transferring the data, whether you're using an external drive or a cloud storage service.  Doing so protects the files from being corrupted, at least to some extent, and the data will take up less space too.

You can download the EA App here:

https://www.ea.com/ea-app#downloads

When you install it and sign in, you'll be able to download your base game and packs.  I wouldn't recommend trying to transfer this data, as there's a lot of it and the EA App might insist on downloading it anew anyway.

Thanks.

I'll just transfer files manually. If anything lacks, my old computer is still going strong so I'll just need to plug it in to get access to the current game files. I think the most shaky thing might be the EA app, s I will try running a new save to check that all DLC is found, before I add my old files.

Simmerville  Let me know if you need any more help with the setup process.