I finally managed a clean media migration with my 90K + items in the library. My approach was to aim for parallel libraries (iTunes, Music, Apple TV) for a while.
1. I set up iTunes to work under Catalina as noted in other posts.
2. I scrubbed the library (incompletely, but pretty well) to make sure it was clean.
3. I ran Library>Organize to check for dead files. I then scanned the listing for missing and fixed any issues. (Doug has MIA that you can use under Mojave.)
4. I cleared out the following folders:
~/Music/Music
~/Movies/TV
~ /Library/Containers/com.apple.iBooksX* - deleted containers
5. I set up another location for media storage. For my 3+ TB library that was on another disk. On it I used a storage hierarchy suggested by the default Apple step in the home folder:
Media/Music/Media
Media/TV/Media
Media/Books/Audiobooks (not currently used)
6. I launched Music 1.0.2 with Option depressed, pointed it to the iTunes db, and it updated perfectly
7. I used Preferences/Files and pointed to the new storage location
8. I did not let it organize files using the default for fear, it might delete the old. I used the Files/Library/Organize instead and selected to copy the library to the new locations leaving the old files in place
9. Ditto for Apple TV. I just launched it and it loads all movies and TV shows. I also migrated its storage.
10. Books imported the Audio Books perfectly and still had my Audible authentication. I think it is using the files in place, but does not have a migration feature. I am copying to the new location and will try importing those.
11. After a little bit Media Sharing using Preferences worked on my AppleTV, but I had to kill the App to see the new content.
It will likely take most of the night to copy all that stuff and really see, whether all is well.
1. I set up iTunes to work under Catalina as noted in other posts.
2. I scrubbed the library (incompletely, but pretty well) to make sure it was clean.
3. I ran Library>Organize to check for dead files. I then scanned the listing for missing and fixed any issues. (Doug has MIA that you can use under Mojave.)
4. I cleared out the following folders:
~/Music/Music
~/Movies/TV
~ /Library/Containers/com.apple.iBooksX* - deleted containers
5. I set up another location for media storage. For my 3+ TB library that was on another disk. On it I used a storage hierarchy suggested by the default Apple step in the home folder:
Media/Music/Media
Media/TV/Media
Media/Books/Audiobooks (not currently used)
6. I launched Music 1.0.2 with Option depressed, pointed it to the iTunes db, and it updated perfectly
7. I used Preferences/Files and pointed to the new storage location
8. I did not let it organize files using the default for fear, it might delete the old. I used the Files/Library/Organize instead and selected to copy the library to the new locations leaving the old files in place
9. Ditto for Apple TV. I just launched it and it loads all movies and TV shows. I also migrated its storage.
10. Books imported the Audio Books perfectly and still had my Audible authentication. I think it is using the files in place, but does not have a migration feature. I am copying to the new location and will try importing those.
11. After a little bit Media Sharing using Preferences worked on my AppleTV, but I had to kill the App to see the new content.
It will likely take most of the night to copy all that stuff and really see, whether all is well.