How to use TouchCopy's Copy History
As a track is successfully copied, TouchCopy will mark the track as copied. Whenever you connect your device to TouchCopy - TouchCopy will detect the music you have previously and successfully copied. This allows you to know which tracks have been copied and which have not.
TouchCopy will mark tracks it has copied successfully with a icon under "Copied" on a PC, or with a red check under "iTunes/Music" on a Mac. TouchCopy will also provide info of any songs already in your iTunes library or on iCloud, as detailed in TouchCopy reports.
Note that if you previously copied your device music to your computer hard drive with TouchCopy and now you wish to copy your music to iTunes/Music (or the other way around) you should clear the history of copied tracks, as TouchCopy does not differentiate between history of copying to PC or iTunes/Music.