I'm guessing you have some code in it at least, and you didn't try compiling it and it will not, or you did and it won't compile. That is one reason why it won't convert.
The more we hear silence, the more we begin to think about our value in this universe.
Paraphrase of Professor Brian Cox.
See if my article on this topic helps you find the problem: Why can't I create an ACCDE file? (isladogs.co.uk)