iTunes, Match, music grayed out

See Identify cloud status icons in your music library on your Mac or PC - Apple Support. You want all of your content to be matched or uploaded. Try File > Library > Update Cloud Library.

Note there is no benefit to having iTunes Match at the same time as Apple Music.

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Ideally you'd move your library properly rather than relying on iTunes Match to copy it. There are bits that iTunes Match won't capture, including any content that was still waiting to upload or had a problem in the original library, excluded content, video, podcasts, etc. See Move your iTunes library to a new computer - Apple Community for a way to move the whole library.

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Does the media exist locally on your current computer? I.e. are you waiting for it to upload from that computer, or are you hoping to recover media that was in the process of being uploaded from a previous computer?

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