I've seen a couple people voice that they've experienced this problem but I have yet to come across a solution. I am simply trying to share my itunes libraries between my PC (Vista) and my new iMac. I set both computers to share and look for shared libraries. My PC detects and can play the mac library fine. The problem is that the Mac only occasionally detects the PC library. And, IF it detects it, I can only listen to about 30 seconds of a song before the shared library disappears. I know I could try the new Home Sharing option but I haven't heard great things about it, nor do I have an itunes store account. I would prefer a solution to the traditional shared library option.