@qimmig Please create a new admin Windows account and try playing there. Make it local, as in, don't link it to your Microsoft account. You'll be able to (try to) launch Sims 4 without reinstalling anything, but your saves and other content won't be available. That can be addressed later; for now, just let me know whether the game works at all.
The game does work when I try it in that way, thank you. What do I do from here? Thanks a lot!
@qimmig That means the problem is something in your main account. One possibility is borked permissions. If you have an Electronic Arts folder inside Documents, please make sure it's empty, then delete it. (I mentioned moving the Sims 4 folder inside Electronic Arts to the desktop, but if you put the folder back later, move the Sims 4 folder to the desktop again before deleting the EA folder.)
If that doesn't help, try reseting permissions with the takeown command. First, run a Windows search for "Command Prompt," open it, and enter this command:
reg query "HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\Shell Folders" /v "Personal"
The location you see is what you'll use for the command. The command itself is this:
takeown /F "[file path to Documents folder]"
So it will probably be one of these, but double-check anyway:
takeown /F "C:\Users\username\Documents"
or
takeown /F "C:\Users\username\OneDrive\Documents"
Write your actual username for this Windows account (your main one) instead of username. Since the syntax needs to be exactly right, please copy this command to a Notepad file, substitute in your username, and then copy that string when you're ready to use it. Hit Windows key-X and choose either "PowerShell (Administrator)" or "Windows Terminal (Administrator)," whichever option is offered, paste the command into the window, and enter.
Then restart your computer and try again to play.
If that doesn't help, please see this post for further troubleshooting:
You'll of course apply these steps to the Documents folder your account is using, wherever Command Prompt told you that was.
If none of this helps, please list the full file path to Documents that you see when running the Command Prompt command above.
Unfortunately, none of that worked.
The file path is: \\LAPTOP-(my laptop)\Users\Emily\Documents\The Sims 4 or C:\Users\Emily\Documents\The Sims 4 , I'm not sure which one is correct.
Thank you for all of your help, it is much appreciated.
Edit. I forgot to ask, but what could have caused this change? It worked just fine the other day, and when I logged onto my computer one morning and tried to open The Sims, it stopped working. I hadn't changed anything that night or ever in my time of playing The Sims 4.
@qimmig If you use a third-party antivirus, it could have updated and decided to block Sims 4. Some programs aren't careful and "protect" certain folders they flag as at risk by changing permissions on the folders, although takeown should have addressed that.
It's possible, if not particularly likely, that your computer has a virus, so that's worth looking into as well. If you'd like to test, download Malwarebytes (the free trial is fine) from here:
https://www.malwarebytes.com/mwb-download
Open it, click Scan > Custom Scan > Configure Scan, check all the boxes both for all scan types and for your all your drives, and let it do its job. This could take anywhere from a few minutes to several hours, depending on the amount of data and whether the scan finds anything., so you may want to set it to run while you're doing something else. Please attach its report so I can take a look.
Please also run a dxdiag and attach it to a post.
https://help.ea.com/en-us/help/pc/how-to-gather-dxdiag-information/
The correct file path is C:\Users etc., but the other path is the same location, just named differently.
