e-file failure

it will not let me e-file my federal return. I get to the point to e-file  but it will not do it. After hitting the transmit button it says "But before you e-file, we need a little more information that we didn't need earlier". So I hit the CONTINUE button and it only brings you back to the beginning of the filing selection screen. It seems caught in a circular loop basically saying it needs something but does NOT say what that is and/or allow it to be addressed. I have the latest updates on my desktop so how is this problem fixed? Please advise ASAP as filing time is very near. Thanks!