This post has been updated. See details below.
I was excited to try out the new Home Sharing feature in iTunes 9. The feature isn't as new as some reports suggest--it's been possible to share iTunes libraries among computers in a home network for years now, but the experience was pretty limited.
You couldn't play DRM-protected songs in a shared library, couldn't create playlists from a shared library, and most importantly, couldn't physically transfer songs from a library on one computer to a library on another. Home Sharing promises to change all this, so I gleefully updated iTunes on my Windows XP PC and my MacBook (which my wife has adopted), and enabled Home Sharing on both.
For a brief shining moment, my Mac (which is almost music-free) was able to see the 3,500 songs stored in iTunes on my PC. The transfer button was just sitting there, waiting for me to start moving as much of my music as I wanted over to my Mac.
But instead of moving ahead, I had to mess around. Long story short, my wife and I have separate user accounts on the PC. There are some songs by some artists (like Journey) that are in my wife's iTunes library on the PC but which I've made sure never show up in mine (I can't stand Journey). So I decided to try to share her library with the Mac.
I closed iTunes on the PC, logged off, logged onto my wife's user account, opened iTunes, and tried to set up Home Sharing. It let me authorize with iTunes--which is necessary for turning Home Sharing on--but as soon as I authorized, the Home Sharing icon in the left-hand column disappeared.
OK. So I logged off my wife's account, logged back on to the PC as myself, and went back to my iTunes library. Now I couldn't see Home Sharing at all. I used the Advanced menu item to turn Home Sharing off and back on--no luck. I went to the Mac and turned it off and back on--no luck, and that made Home Sharing disappear on that copy of iTunes as well! I rebooted both machines multiple times--no luck.
Now every single time I want to turn Home Sharing on, it lets me authorize, then as soon as I hit the "Done" button, the Home Sharing icon disappears. My guess is that it has something to do with trying to authorize two libraries on the same PC with the same iTunes account, but there's no online support for iTunes 9 yet, so I can't tell. (And before you ask, yes, I have both the "Share my local library on the network" and "Look for shared libraries" boxes checked on iTunes on both computers.)
Lesson: if it's working, don't touch it! Transfer that library, and get the heck out. And if anybody else has had this bug and knows how to fix it, please let me know in comments below.
Update, September 11: I turned on my Mac and PC this morning, started up iTunes, and the Sharing folder and Matt Rosoff's Library icon appeared on both. I haven't changed any settings in iTunes or in my firewall software. I'm not sure what happened, but my advice to those of you who are seeing this apparent bug--and judging from the comment stream, it's not uncommon--is to shut everything down, start up again, and make sure that iTunes is open on both computers.
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