I copied 27 files from a flash drive but it has only 26. Virus?

I just copied some mp3 files from a flash drive that came from a different computer and my computer copied 27 files. In the folder there are only 11 mp3s and when I made the hidden files visible, it shows 26 files. Is the 27th a virus? There was a long pause while it was copying. There was also a long pause while the flash drive was scanned by Kaspersky. Now I'm worried I have a virus that I can't find. Any help would be much appreciated