Audio Notetaker will periodically make a backup copy of all open projects in case your PC, or Audio Notetaker itself, shuts down unexpectedly. Should this happen, Audio Notetaker will automatically display the recovered project tabs the next time you run it. It will only do this once, so you must decide whether to save or delete the recovered project(s) before exiting.
 

You can set the backup time interval, and turn it off altogether if you so wish, in App Menu → Settings → General.