Unable to select Wake for Ethernet Access

I like the new iTunes Home Sharing option in iOS 4.3 and have set it up for use on my iPad but the issue I'm having is with the computer end.
I have two Mac's a Macbook Pro and a Mac Pro, each running the latest version of Snow Leopard.

I have set up iTunes for Home Sharing. That is not the issue. The issue is I of course have the computers set up to go into sleep mode. The problem is often when I decide to use Home Sharing on my iPad the computers are in sleep mode and when doing a google search I learned that I need to go into the Energy Saver section of Preferences and select something similar to Wake for Ethernet network access.

On the MacBook Pro under Energy Saver there is an option called "Wake for Ethernet Network Access" I selected this and it allowed me to keep it checked and now it works fine.

My largest library is on the Mac Pro and the problem is under Energy Saver and Power there is an option that says Wake for Ethernet Access but I can check it and I get a box that says:
"When Wake for network access is enabled, you may hear your computer wake up occasionally. This informs other devices that your computer is still available on the network. I select okay but even before I select Ok the checkmark by Wake for Ethernet network access is already unchecked.
Unfortunately I can't figure out a way to keep it checked. Does anyone have know why this is going on and why I can keep it checked?

I don't think this makes a difference but my MBP is connected via Airport to an Airport Base Station Extreme and my Mac Pro is connected via Ethernet to the ABSE. The Mac Pro is approximately 2 1/2 years old, the MBP around 4 1/2 years old.

Also, if I am correct I have to keep iTunes open to have Home Sharing works. Is that true?

Hi

For your question right at the end about keeping iTunes open for Home Sharing, that is absolutely true yes.

As for the checkmark, when you open System Preferences > Energy Saver, click the lock at the bottom to lock access to the control panel. Then click it again to unlock it and type in your password. Could just be a glitch that needs you to authenticate it again. Hope fully that should sort it out.

You could also try deleting the file /Library/Preferences/SystemConfiguration/com.apple.PowerManagement.plist and restart. That's the library at the top level of the drive, not in your home directory. Then go back to System Preferences > Energy Saver and set them up as you wish. see if they stick now.

If not you could try repairing Disk and Permissions, by booting into your OSX install DVD, going to Utilities > Disk Utility > First Aid.

Hope one of these helps

- Simon

Hello Simon,
Thank you for your help. It was some type of glitch and once I locked and then unlocked it it works fine now.

Glad I could help!

- Simon