You need to go an older version of iTunes.
posted by king_penguin
I went back by :
1, deleting iTunes 12.7 from the Applications folder. I had to use 'get-info' on it to change it permissions so that 'everyone' had 'read & write' access so as to get around the 'required by OS X' message e.g. How to Uninstall iTunes in Mac OS X
2, downloaded and installed 12.6.2 (assuming that's what you were running) from https://support.apple.com/downloads/itunes
3, in Finder go to folder /Users/username/Music/iTunes (where 'username' is the account that you are using on the Mac)
4, rename or move the 'library.itl' file that's in it (that will have been updated by iTunes 12.7 and won't be backwards compatible with 12.6.2)
5, copy the previous version of that 'library.itl' file back from the 'Previous iTunes Libraries' folder that's there (it will likely have the date that you updated to 12.7 as part of its filename e.g. iTunes Library 2017-09-21 if you updated today ; and remove that date from its name so that it's just 'library.itl').