I am having the same problem. Was building in the game last night and tried to log in today and got the same error message "System cannot find file specified". I uninstalled all my mods awhile ago, long before this issue popped up. I tried to run a repair, but the repair just kept starting over when it finished so I cancelled it and restarted my computer to see if that helped. Still getting the error message and no option to try and repair again.
Update: The repair option came back and finally ran all the way through. I'm back in my game. Just in case it works for someone else.
I had this issue again today. The first time two weeks ago, the app called for a repair, which worked fine for me. This time, it went into a continuous repair loop, so I stopped it, and restarted my computer. It still stated file not found, so I opened just the EA app, which took three tries, and went to library and clicked on the three dots in the corner of Sims 4, and used that repair option. My game is now loading normally again.
