"Network settings have been changed"

Simple fix is to go into the Security preferences, and enable the option for "Require password to unlock each System Preferences pane." Longer fix would involve creating a new network location, pulling the preferences.plist from /Library/Preferences/SystemConfiguration, restarting and re-configuring your computer's network settings.

 

Hi All,

I had this same problem recently I tried the lock settings trick but it didn't work for me. I found another fix that did work:

Go to Library/Preferences/SystemConfiguration and delete the following (suggest make copies to the desktop first if in doubt):

com.apple.airport.preferences.plist
NetworkInterfaces.plist
preferences.plist
com.apple.nat.plist

All these files will regenerate as necessary. If you're using Airport or Internet Sharing you'll have to reestablish the appropriate settings.

Thanks to Maddog who originally found the fix.