Me too. I find that about 3/4 of the songs in the library sound like "The Chipmunks on acid with an alien back-up band"......HORRIBLE ! I see one of the replies mentions that songs purchased through the store work...I thin I have discovered the same thing. After I upgraded (after multiple notices to do so....next time "NOT"), I synced my iPhone and iPad and all songs seem to work fine on those devices. I use iTunes more as a tool, since I am a musician. Fortunately, everything seems to work OK using Winamp, so at least I can work with that and that also tells me that my sound card is not bad or there is something wrong with my computer.
I understand that problems can come up and I am usually forgiving. Today I don't feel quite that way. I wasted much of my weekend, uninstalling, troubleshooting, tried downgrading only to have the problem with the library not to work, etc, etc.......uuuughh!
The most frustrating thing of all.....how do you contact a person, or at least get an e-mail address, so you can report it...and hopefully get the instructions on how to fix this? I have invested a lot into this stuff (iPhone, iPad) to use as support tools.....with the main purpose of using iTunes on my PC.
Anyone know how to contact a "real" person that could provide assistance ??