SDK does not contain any platforms. error (android)

By default sdk was installed under the 

C:\Users\<user_name>\AppData\Local\Android\sdk\ directory

Not inside the

C:\Users\<user_name>\.AndroidStudio2.1\

So now change your sdk path by browsing above specified path. And you have to add JAVA_HOME path under System Variable.

You can change the sdk path by copy pasting the entire sdk directory from C Drive to any new location.