Cooking map issues

when i start my ark dev kit i get this warning message " 1. UE4Editor-MetalShaderFormat.dll"
when i click the cook map button the same message appears .
while the map is cooking i only get warning messages and no succes messages most similar to this
“ogpackagename:warning: found ambiguous file name”
once cooking complete the file one steam is only 0.003 mb big
any ideas ?