I am having this same issue. Never touched the vehiclelayouts.meta file. However I did the following and made a mistake :
-My game was working perfectly fine. (I have custom cars for all police slots, fbi 1& 2, and sheriff 1 & 2)
-I wanted to download the new LSPD pack from TOY, which included a required vehicles.meta file
-I added Police1, Police2, and Police3 from his pack and put in his vehicles.meta file BEFORE I MADE A COPY OF MY OLD META FILE!!!
My game now crashes every time I get into a vehicle, I have tried for hours trying to backtrack my steps. But since I do not have my old META file, I can no longer use my old PD cars.
I did not plan on using TOY's cars, because I was not a huge fan after trying. But I think I will now be forced to use his, because his META file overwrited mine.
Any ideas on how to help? I am so upset, as I had a great pack of custom PD cars that no longer work.