Currently Being ModeratedNov 19, 2012 4:48 PM (in response to AnneOconnor)
We need more information on your configuration, the source of your music, do you use Match, etc. I have never authorized my computer and never bought anything from the iTunes Store and all my collection is there, so de-authorizing as such shouldn't lose your library.
Currently Being ModeratedApr 3, 2013 9:14 AM (in response to AnneOconnor)
uninstall itunes and just install itunes again or maybe you just didn't update your itunes