I had the same problem and the map wouldn't work at all. The files should be in the folder
~/Library/Application Support/iPhone Simulator/[6.0 and above]/Library/Caches/GeoServices/Resources
In my case I had 3 styleproto files in there including firstname.lastname@example.org which I duplicated and renamed to default.styleproto. Now the map works but all the icons are @2x size, which is very annoying. I thought of using the default.styleproto file from a different computer but it didn't have it either.
Any real solution to this?