Version: 2017.1
public void LogError (string warning, Object context= null);


Logs an import error message to the console.

Pass an asset as the second argument to link the error to the asset in the editor.

See Also: Debug.LogError.

    class CustomImportSettings extends AssetPostprocessor {

function OnPreprocessTexture() { var importer : TextureImporter = assetImporter; if(!importer) LogError("Texture doesnt exists"); } }