home sharing does not work with new mountain lion update.

Well it's not a setup problem with my IMac. The same thing is happening with my MacBook air. I wonder if it is a software problem or caused by the firmware update? I am going to go back to Lion on my iMac and see what happens.

I take back the bit about it working when the computer is asleep... it works with display sleep only.

Same trouble here, Apple should do something is anoying as ****

Bought an ATV3 about a month ago and had no issues till 3/4 days ago. All of a sudden I couldn't access my iTunes Library and kept getting a message to make sure Home Sharing was on, iTunes was running and all devices were on the same network. I tried all the tips here and on the home sharing troubleshooting guide with no success.

I called Apple tech support and she made me do it all again and nothing worked. She then said the only things left to do to try were to reset my router and reset ATV.

***So I unplugged Netgear router for 30 seconds and then waited for it to come back online. Then I went and reset the ATV as per her instructions: hold the menu and the arrow down buttons simultaneously for 5 seconds and then release. ATV shut down and rebooted and then Voila! my iTunes library was instantly accessible. It's been trouble free for over 24hours now.

I have a feeling it's an ATV issue because I'm still running Snow Leopard.

Hope this helps some of you!