Fake or not It depends. What was its size, Track Length.. etc.
Generally, a 70 min Mp3 will have approx 65-90 mb size. For 128 bitrate that is. Higher the bitrate, more is the size. If
Anyway, try searching for it in with Windows search. OR look for it in the folder in which you saved it. Look at the last files. Generally when arranged by name, completed files are always in the end.
Most importantly, if none of this works, run a virus scan That will keep problems away (Keep peace of mind)
But so far, I have always been able to find completed files without problems.