Q: Why are some songs greyed out on iTunes?

You can check all selections by going to the My Music, then on upper right, select Songs instead of Albums, select one song, then press Cmd-A to select all music, right click/two-finger click, in the context menu select "Check Selection," and done.

some songs are on multriple albums. So when a song is greyed out, just search for the song and youll be able to download it as a single.

I wish I would have read this 2 hours ago! This is what solved the issue for me too. Thank you very much.

Thank you!  This solved my problem that I never had before til today.  Wham,did exactly what you instructed and frustrated problem went poof! Thanks!

Thank you!!!  I don't know how I did that in the first place, or how I missed it either! 

be prepared that doing this is going to lose all ur saved iCloud data for songs already transferred. tried this and lost everything.

This is really bizarre. The "check" step worked perfectly for me. The reason I was really confused is that all the songs in the playlist played perfectly fine yesterday (!!!), and today some of them became unchecked randomly. ***? I did not "uncheck" them for sure. Nobody is using this computer except me.

Apple is completely silent about this whole issue with iTunes and Music app on iPhone as if it does not exist. in fact, there are so many issues, I do not even known where to start. For instance, the "Shuffle" button issue is completely impossible to comprehend.

I agree.  I definitely did NOT go in and 'un' check the box either.  Weird

I don't know if someone else has posted this yet, but I was experiencing the same issue, and then when I figured out what the problem was, proceeded to connect my palm to my face very forcefully.  At some undetermined point, a large section of my music had been "unchecked", that is to say that all of the music has a checkbox next to it, and apparently checking v. unchecking affects the playability of the music.  So all I did was select all of my music by song, right click and click "check selection" and all of my music was suddenly playable.  I hope this helps somebody.

Wow! Thanks!! You have answered two of my questions tonight that I have been having problems with.

Thank you so much. marking all the songs as checked fixed my grey issues. Don't know how so many of my songs got unchecked.

Thank you for that "Duh" moment!

This was the answer! I ended up doing a "Ctrl = A" to select all and then adding checkmarks to the entire catalog. I can go through later and uncheck just a few items. Thanks so much!

This worked! Thank you. What is the check/uncheck section even for other than fixing brokenness

Tried this and just lost 600 songs from before I had Apple music. All Apple music has been since I had it is a disaster!! Constantly have grey cloud icons buy all my music and it doesn't allow me to listen to any of it, and now losing 600 songs just tops it off...