Q: what about my music libary on mac pc?

I am completely failing to make any sense out of either your topic or your post content. "Mac PC"?  "PC" usually refers to a computer running Windows.  Macs run OSX, unless you are an advanced user in which case it can run both.  Your profile says you are using a MacBook, and you posted this in the iTunes for Mac forum, so I don't see where the Windows update comes in.  If you are using Windows and updates are causing a problem then you are better off posting in the correct iTunes for Windows forum, or posing the issue to Microsoft who produces the updates to Windows.  If you do post in the iTunes for Windows forum you will need to be a lot more specific about the actual issues you are having.