Posted By: FAQster Your network settings have been changed ... - 12/08/09 04:32 AM
The problem: you've gone to the Network pane of System Preferences, and a dialog pops up that says: "Your network settings have been changed by another application." You dismiss the dialog, but it comes right back, again and again. There's no obvious way out of the loop. Users have been known to force-quit System Preferences in desperation.

Fortunately, there's a rather simple if highly non obvious remedy.

First, if you're in the loop right now, here's how to get out without force-quitting anything. Notice that after you dismiss the dialog, there is a brief delay (less than a second) before it re-appears. You can use that time to get off of the Network pane. Position your mouse over the back button (or the Show All button). Use the enter key to dismiss the dialog, and then immediately click the button.

Now comes the non obvious part. You see that padlock that appears in the lower left corner of many of your preference panes? There's one of those on the Network pane (but don't look right now, or you'll be back in the loop).

The error message is triggered when all three of the following conditions are true:
  • You go to the Network pane.
  • The padlock is unlocked on arrival.
  • Your network settings include an unencrypted saved password.
We're going to fix that by getting your passwords encrypted, but you have to sneak up on them. Here's what you do:
  • Go to any other preference pane that has that padlock (the Security pane is a good candidate) and lock it.
  • Now go back to the Network pane. You won't get the message because the padlock is locked.
  • Unlock the padlock. It's safe to do that now, because you're already on the Network pane.
  • Scan all of your network settings (not just the active location) looking at each PPP or PPPoE pane of every interface, looking for where you have "Save password" checked. Where it's checked (typically only one or two places), uncheck it and re-type the password (which will cause it to be re-checked).
That's it. Each saved password needs this treatment only once. The repair is permanent. You can leave the padlock unlocked if you desire.

What if you can't remember your password? The easiest way to recover it is to open Keychain Access (in /Applications/Utilities) and look for email passwords. A PPP password is usually used to connect to an ISP, which will use the same password for the email account they give you. Your email password is already in the keychain, and Keychain Access will divulge it in exchange for your keychain password.

For the curious, here's what happened. Apple used to do something really stupid: they saved PPP-like passwords unencrypted in /Library/Preferences/SystemConfiguration/preferences.plist. (The passwords were Base64-encoded, but that hardly counts as encrypted.) Then they realized their mistake, and issued a security patch. These passwords are now stored in the keychain, where they should have been all along.

But the Tiger version of that security patch forgot to move the passwords to the keychain. When you go to the Network pane, they read this preference file, see the unencrypted password, and think it must have been put there by some piece of non-Apple software. If the padlock is locked, they know they can't do anything about it, so they ignore the problem. (They haven't forgotten how to use unencrypted passwords; they just don't like other software still mucking with the file in the old insecure way.) If the padlock is unlocked, they give you the error message, then re-read the file to get back in sync with whatever that "other" software has done, completely overlooking that they haven't actually done anything to improve the situation.

Written by ganbustein in Fixing dialog loop in Network System Preferences.
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