iTunes cannot locate any songs in library

That suggests to me that you need to move the folder iTunes Media from /Users/darrylj/Music/iTunes/ into /Users/darrylj/Music/Darryl's iTunes Library/ although that won't be quite so easy if there is already an iTunes Media folder there that has content inside it. You can merge one version of iTunes Media with another if you hold down option as you drag the folder from one parent folder to the other. See macOS Sierra: Organize files in folders. Ideally you'd have a backup of all this elsewhere before you start just in case something goes wrong so you can at least revert to the current state of affairs.

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Make sure that your profile has full read and write permissions to the iTunes folder and all subfolders. Use Get Info on the iTunes folder in Finder. Click the lock at the bottom right to make changes. Make sure that Locked isn't ticked and that your own account has Read & Write access, then use the gear icon to Apply to enclosed items and confirm.

If your media folder is not stored inside your main iTunes library folder then make the same changes to the media folder.

This should resolve the issue of iTunes not retaining changes you make to the library. Do you have any third party anti-virus software? If so exclude the iTunes folder from real-time AV protection.

See also this post: Re: iTunes & External Hard Drive. My script is only for Windows but some of the other information there might help, and I might have further advice if you can supply the three details at the end of it.

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Signing out of the iTunes Store and back in again should resolve cloudy duplicates, though it could cause iTunes to discard any previously downloaded Apple Music tracks. Again a little more information about exactly what you're seeing might help. See About iCloud Music Library icons and status - Apple Support. If you turn on the status columns you'll be able to see if there is anything that Apple Music sees as a duplicate, or other issues such as files that are waiting to match or upload.

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See Make a split library portable. Ideally your library would be in this shape. An iTunes folder, containing an iTunes Media folder containing folders for various media types, and then split further by say (album) artist and album for music. Apple Music DRM tracks get their own Apple Music subfolder inside iTunes Media. Work out which your active iTunes Library.itl file is by Date Modified, then with iTunes closed arrange the components of the library in the correct shape, use option-start-iTunes to reconnect to the desired .itl file if you move it. Once you've got the basic structure fixed you can try repairing links where iTunes doesn't work it out for itself, or use the technique from earlier to move things to where iTunes is now expecting to find them.

tt2