Multiple AppleIDs across two iMacs I have an old iMac, but also acquired a new one, and now run them both, side by side. I set up the new one to have the same AppleID as my old iMac, which has an enormous amount of music in iTunes. While there are a few iTunes purchases in there, mostly this music is from my CD collection that I imported over the years into iTunes on the old iMac.

I thought that these would sync, but that music won't appear on the new iMac's iTunes, even though its signed in with the same AppleID credentials.  To confirm the credentials are identical, I can see (for example) that my "Purchase History" in iTunes contains identical information on both iMacs.

So why is it that my imported CDs (in the original iTunes) can't be seen on my new iMac?   many thanks for any thoughts - very concerned that I'll lose all those old songs, and all the effort it took to import them - I had hoped to migrate it all to the new iMac :(
By default, iTunes is not going to copy your Music CD tracks from one Mac to the other, though Apple does offer more than one paid method to have them moved for you.

There are free ways too, multiple of them, and this article from Apple goes over some options: https://support.apple.com/en-us/HT204318