Stubborn MP3 Sample

Does anyone have any idea why I cannot edit a certain mp3 file? Trimming it in FL Studio's playlist then exporting it does not work. Trimming it in Edison doesn't work. Trimming it in Audacity doesn't work. It is not set to read only, and I know I have sufficient privileges to edit it. I am exporting it as it's own separate file, with it's own name, in it's own folder. Yet it still reverts itself to before I trimmed it in whatever program. Could it possibly be corrupted in some way?