KatSim

I have downloaded the sims 4 tray importer for my MacBook 4x this morning. First said I needed another app to open the contents, I bought that app. When trying to open with RAR pro it says the file is not compressed and can't be opened. The file will not self extract and I can't use it. My sims game is broken even after removing mods and CC. I think something is hidden and I need help to repair my sons game but this is the only forum I have found that gives me a way to do it, but nothing at all works on sims 4 tray importer for Mac as I can't even open the file. What am I doing wrong!!!???? Please help before I throw the entire game away from frustration