iTunes does nothing when i drag music to my library how can i fix this?

Try Repair security permissions for iTunes for Mac - Apple Community. Alternatively try placing copies of the files in the Automatically Add to iTunes folder in your media folder. If the files get moved to a Not Added folder you'll know that iTunes doesn't like them, but not why.

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Perhaps iTunes doesn't like the output of the conversion program. It doesn't help that iTunes will silently reject anything it doesn't want to add to the library. Try using the Automatically Add to iTunes folder and confirm that the items get moved into the Not Added subfolder.

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Try some other songs from other sources. Works fine here. Make a copy of something already in your media folder and see if the copy will add.

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Yes, iTunes doesn’t support FLAC.

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What is the source of these files? Recent changes at YouTube appear to have broken some conversion programs.

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