Mac OS 10.4 Network Preference Problem "Your network settings have been changed by another application" Solved

I helped one user to solve a strange network preference problem today. The machine is a Macbook Pro running 10.4.11. According to the user, after he updated it with the 2008-006 patch from Apple, he started to get this message whenever he clicks on the Network preference in System Preferences.

Your network settings have been changed by another application.

If you click on OK, the message would pop up again right away and you cannot do anything about it until you force quit the System Preferences.

There is a discussion thread on Apple Support forum, which gave me hints to solve the problem. It turns out the security patch changes the way of saving PPP (or PPPoE) passwords. If you have a network profile that has PPP (or PPPoE) passwords, you would run into this problem. The way to fix it, is just resetting the passwords.

Here are the steps.

  1. Log on as a administrator on the machine.
  2. Run “System Preferences”.
  3. Click on “Security”.
  4. Check “Require password to unlock each System Preferences pane”
  5. Click on “Show All” and then click on “Network”
  6. Now it’s the fun part. You have to find any connection that has PPP or PPoE passwords saved. When you find it, uncheck “Save Password”. Enter the password and check “Save Password” again. Note that you need to click on the Padlock on the lower left corner first to make changes. Apply the changes as needed.
  7. You can go back to the “Security” pane and uncheck “Require password to unlock each System Preferences pane”.