Sims 4 opens but once it gets to logo it closes and shows an error message saying that sims 4 has stopped working- and that's it. I do of course have mods, my mods weren't working so i repair sims and did the 50/50 method. But as soon as I put in my last mods it stop working- so i took them out again and it still refuses to work. the mods i put in used to work.
Remove all of them to see if the game starts.
For example, move the mods folder from C:\Users\Username\Documents\Electronic Arts\The Sims 4 to your Desktop and start the game.
Some mods might not work together, so even if the game starts with two mods separately, it might not work with both of them.
If that works but you want to keep your mods, you can try some different things to sort out the ones not working:
If you cannot get it to start even without the mods,
Reset your files to factory settings
If putting back one of the folders was problematic and you did not work it out, please post a reply and we'll see if we can find what your problem is!