Skimmed thru the whole 10 pages of the thread and didn't notice this fix.
I could have totally missed it though.
Anyway, it is the ONLY solution that worked for me.
Not saying it's the "best," "least complicated," or "will totally work for you" option.
I will say that it is the "most ridiculous" option.
If nothing has worked for you yet, why not try it just for kicks?
1) Hate your life.
2) Click "Playlists" up there at the top of the screen.
3) Click on the playlist "Purchased."
4) Select the tracks you are having trouble (as described by original poster) with —they'll have those little exclamation point thingies next to them.
5) Make a playlist from those tracks.
6) Click "My Music" to return to your library.
7) Search for the missing track/album in your library.
8) In the track list portion (don't think it works if you click to play the whole album) click the first—or any—track with an exclamation point next to it.
9) When you get that "do you want to locate it" pop-up, click "CANCEL." Yes, you read that right.
10) Now take a look at the track you couldn't download. There should be the little cloud next to it.
11) Click on the little cloud.
12) Voilà ! The track should download.
13) Repeat steps 8-11 for every single track you're having the problem with.
14) Turn that frown upside down.
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