One use to have to delist my old iMac from Music before migrating to my new iMac or some of my music will not play because I reached the limit for the number of computers for some recordings can play.
[Re-Titled by Moderator]
iMac Pro, macOS 15.2
See Authorization vs. association - Apple Community for background. You are allowed at most five authorized computers and ten associated computers and devices. Ideally you would deauthorize a computer you no longer wish to use before you wipe or dispose of it, however should you forget to do so it is possible to deauthorize all computers and then authorize up to five as needed. Associations can be released remotely making them slightly less of an issue.
See Move your iTunes/Music library to a new computer - Apple Community for advice on moving the library across.
tt2
Delisting old iMac from Music before transferring to new iMac
