The stuff below is something I copied an pasted from a support article several years ago. The article no longer exists as such and now you have to painstakingly work your way through Apple's new user information files to try to find information. I probably also took it from a Mac version. Still, it might provide you with some leads.
About iTunes library files - iTunes - Official Apple Support - new with iTunes 12.2, preference setting to not create .xml
"About the iTunes Library.xml file
The iTunes Library.xml file contains some, but not all, of the same information that's stored in the iTunes Library.itl file. The purpose of the iTunes Library.xml file is to make your music and playlists available to other applications on your computer, such as iPhoto, Garageband, iMovie, and third-party software, in OS X Mountain Lion and earlier. These applications use this file to make it easier for you to add music from your iTunes library to your projects. By default, iTunes 12.2 and later doesn't create an iTunes Library.xml. If you're using OS X Mountain Lion or earlier or a third-party app that uses the XML file, you need to enable Legacy library XML support"
Do you still see a .xml file? If you do, have you tried moving it elsewhere and then start iTunes to see if it creates a new one?