Re: Sims 4 already installed but Origin asked to download, can't uninstall either

@gisellegionne1  Try trashing TS4_x64.exe, with Origin closed, and see if it lets you repair the game instead.

If that doesn't help, what happens if you just click Download?  Origin might redownload the entire game, but then it should work.

If downloading the whole game would take too long, you can use the files you already have to shorten the process.  Close Origin and move the Sims 4 folder in Origin Games elsewhere on your computer.  Open Origin, click the Download button, and when it starts, pause it.  Then move the contents of the Sims 4 folder you moved to the new Sims 4 folder in Origin Games.  Click Resume in Origin, and it should verify the files that are already present and download anything else missing.  It's still a good idea to let it redownload TS4_x64.exe instead of using your current copy though.