Apple has released a small update to the Apple TV system software, bringing it to version 3.0.1. The update addresses a small issue where synchronized items between the Apple TV and iTunes would disappear until you performed another synchronization.
Information on the synchronization issue that this update addresses is available in this Apple Knowledgebase document: http://support.apple.com/kb/TS3116
To update the Apple TV software, perform the following steps:
- Reboot the device by unplugging it and plugging it back in.
- Go to the "General" settings from the main menu.
- Select "Software Update".
- Select "Download and Install".
The device will restart and show the Apple logo and a status bar indicating the software is being updated. When this is happening do not unplug the Apple TV.
The update is supposed to address the problem, but according to the KB document it may persist even after updating. If it does, try disconnecting the device from the computer and reconnect in the "Computers" section of the settings. Additionally, you can do a factory restore of the Apple TV software, update to version 3.0.1, and then re-sync your content. To perform a factory restore, follow the instructions in this knowledgebase document: http://support.apple.com/kb/HT3199