I cannot access the Advanced page under System Preferences → Security & Privacy to check or change the automatic logout settings. I don't think I can change this setting, and I tried using
sudo in the terminal to change it without success.
sudo defaults write /Library/Preferences/.GlobalPreferences.plist com.apple.autologout.AutoLogOutDelay -int 3600
I'd just like to know how long I can be away from the computer without being logged out. I am on a university Mac desktop.