Moving all playlists from iTunes library to Apple Music

Thank you, turingtest2

Sweejak and any other interested parties: This is not a "helpful" reply, but a (vague) record of personal confusion and blundering.

Somehow, everything's working and unfortunately for the sake of contributing to the Community I don't know what I did to make it all work, finally, after the better part of a day fiddling. I did read everything I found on the subject, but not your post you've linked to, which in retrospect seems clearer to me than most of what's posted in various places under variations on the subject heading. I'm getting old (no, I've gotten old) and was once what was known as a "power user," but that was many years ago, and I found even the apparently clearest instructions difficult to conceptualize and follow. The overall conceptualization of where everything is and how it needs to work together (in old and new systems) is the crucial missing element and difficult (for me, at least) to grasp from text alone.

I didn't do the migration myself from the old computer to the new one. I had my complete (old) iTunes library on an external drive. I suspect the tech who did the migration (known to be highly knowledgeable and competent – but he sent me away for the duration of the process) might have transferred the data from the computer first and then from the external drive. I don't know if that even matters, but it seems to me the contents of the drive would have been seen as part of the old computer if he'd connected it before the migration. (At least that's how Time Machine sees it.) This is conjecture on my part.

As I wrote in my original query, all my "songs" were present, or appeared to be, in the Music app, but "Show in Finder" didn't locate a lot of files (if I remember correctly) even though they were visible if I happened to open the right folder. Playlists didn't appear at all in the app, until at some point I somehow caused them to appear, but they were either empty or had the wrong contents. Finally I hand-transferred my old iTunes Library.itl file – and at some later point (?) I chose it as the new library when opening the Music app, and when I saw everything was there, renamed the new folder that contained all the files from Music1 to Music, (A new empty Music1 folder was created at some point, but now appears to be gone.) (?)

Over the course of two days, every time I went to quit the Music app, a warning told me it was downloading. I did not and do not understand what it was downloading or from where, as everything was present in the library on the old external drive, and all the files seemed to be present already on the new computer. But that might explain the empty or wrong playlists and their eventual population with the right contents.

So, through a long day of blundering and confusion I got everything to work, but I don't remember the details of the blundering, and I don't remember the sequence of the right moves I must have made that finally added up to success. So apologies to anyone reading this who's looking for help. I can't tell you much!

But do study turingtest2's instructions. They might be just what you need: Move your iTunes library to a new computer - Apple Community