Tried them all.
Even songs I paid for are showing up with the gray exclamation point and not found. I have over 1000 songs not found which really upsets me since most of them I paid for on iTunes and the rest I put in the system with CD's.
It seems that iTunes figures out what music is not on their system and stops it from being played. This is why some of the older iTunes music I bought are not showing up.
All music is on my Ipod Classic. Which all them play. All I did is transfer what I had on the Ipod to the iTunes.
It should be that simple since the Ipod itself is like an external harddrive but NOPE! What a let down.
I agree. Apple changed itunes to allow purchases of only music, forcing users to buy and install apps
using the device itself. I can think of no reason to remove this option.

I've used many workarounds
to get itunes to function the way I want. If itunes and apple products didn't work so damn well most of the
time, I would go to a different platform, but I don't know which.
Anyway...Log into itunes with your computer and download all music purchases. I've done this with multiple
computers. I've actually called apple and spoken to a person to resolve an issue. Try that, if necessary.
Did you transfer ipod tunes to itunes on your computer via the following method?