Check the permissions on the folder on the Mac HD and external HD that contain the actual iTunes songs. The permissions should be read/write for you and you would be listed as "<your name>(me)".


On a Mac since 1984.
Currently: 24" M1 iMac, M2 Pro Mac mini with 27" BenQ monitor, M2 Macbook Air, MacOS 14.x; iPhones, iPods (yes, still) and iPads.