I ended up opening the Sims 4 folder within the EA app folder through finder. Moved the entire folder and the “Mods” subfolder to my desktop and renamed both. Then I redownloaded the sims via the EA app for it to generate a brand new sims folder and it has seemed to do the trick for now. I never downloaded any mods but did notice something in the folder when I moved it to my desktop. Hope this helps!
did you find a resolution? im having the same issue !
coming back to this I ended up restoring my computer and setting back up and downloading the game again without any of the previous data/files. after I confirmed that the base game itself would open, I downloaded the packs next and did the same confirming. I took the mods that I use the most and little by little I checked the games behavior and ability to open I put in a loading screen and font mod in and I got the message again. took out the loading screen mod and then it opened as normal. may be an update needed with that one mod OR loading screen/main menu, opening screen mods/overrides may have a particular issue with the current version of the game....im just spitballing here
