I have just updated an iPad 4 to IOS 8; Just before that I Updated iTunes to version 21.0.1. However, I was annoyed by the loss of the sidebar, and when I Clicked on my iPad, no options came up to customise synching or to download items bought on the iPad . In the end , using a system restore, I went back to iTunes 11, and updated it from there. (It did install Ios8 ). I am loathe to reinstall iTunes 12 . Do others have these issues?