I am not sure if nothing was lost in the process. I still haven't deleted the original Music folder on my MBP. It had about 30GB of memory usage and I almost have my SSD full, so I decided to move it. In the middle of it it said there was an error but I didn't read what it was and clicked ok (I think it was just one file that didn't move). When I woke up after I slept while moving it it said 20 minutes left till completion. And then when I checked it afterwards the window showing the moving of files was gone, so I guess it was complete now. I'm shy to delete the music folder though because I'm afraid maybe not everything may have been copied. How can I check if the two folders' contents are identical?