Everytime I open my System Pref's (10.4.11) and click on the Network prefs pane I get a dialogue that tells me 'Your Network Settings have been changed by another Application' The dialogue has an OK button, which when you click it just comes back. The only way to get out of this loop is to quickly select the edit locations menu or press cmd w to get out of the system prefs....

I've..........
reset the pram
reset open firmware
performed all the onyx maintenance and cleaning tasks twice
even deleted the launch services data

Has anyone any ideas what process/application is causing this?

For what it is worth, I did a search on MacFixit and the last post I found with this error was in 2006 and no one came up with a satisfactory solution then.

I then did a Google search and you might take a look at this recent Apple Discussion thread or this Applelinks post that references a number of other discussions on the topic.

Thanks joemikeb and thanks K Shaffer for your tip http://discussions.apple.com/thread.jspa?threadID=1715241&tstart=0

I've cleared the problem (x) by opening the security prefpane and ticked all the box's, then locked the security pane. The network pane then didn't produce any dialogue windows but the Apply Now button could be selected on the Network pane. I've just gone back to my original settings and low and behold the "Your network settings have been changed by another application" dialogue appears again. Which I've just discovered can be switched off by using the padlock actually on the Network prefpane.

I'll try the other solutions on the thread like reinstalling the 10.4.11 update, when I get the chance..... and post the results, but meanwhile using the padlock on the network pane works for me.

This post from Tonza in Apple Discussions worked for me:
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Apple.com > Support > Discussions > Mac OS X v10.4 Tiger > Installation & Setup

tonza
Re: Network Preference Pane Gone Berserk after Latest Security Update (Tige
Posted: Sep 17, 2008 4:28 AM   in response to: Emily Jackson

The System Update has changed the NetworkConfig system program in /System/Library/PrivateFrameworks/NetworkConfig.framework, which I presume is now broken. However, I have discovered two things you can do to reduce the effects of the broken network configurator:
...
2. go to the Security preferences, and enable the option "Require password to unlock each secure system preference". This will do what will happen in the previous quasi-solution, requiring that you authenticate to System Preferences before changes can be made.

I just had this happen on my new to me OLD G3 Yosemite under 10.4.11 - I think after creating a bootable external copy with SuperDuper, booting from it, then resetting the boot system to the internal hard drive.

Any way this thread was a great help - found by Googling the error message. I had no luck on Apple's own support site BTW.

I locked the Network preferences then went and told the Security preferences to require a password for changes. That stopped the serial network settings message as advertised here.

I then unlocked the network settings using the system password and the problem has stopped...wish I hadn't said that....this is clearly system bug they haven't fixed and probaly won't now Leopard is out.

Re: Network Preference Pane Gone Berserk after Latest Security Update (Tige
Posted: Sep 17, 2008 4:28 AM in response to: Emily Jackson

The System Update has changed the NetworkConfig system program in /System/Library/PrivateFrameworks/NetworkConfig.framework, which I presume is now broken.

Cloning my system once a month paid off. I agree that latest security update screwed up my network preferences. And deleting NetworkConfig.framework, and replacing with cloned NetworkConfig.framework from month old backup, fixed problem.

Thanks to Al Bloom MacMaster for insight.

I saw a few references to old location manager preferences causing this problem so I deleted all my locations (fortunately in my case they are easy to re-create) and the problem went away.

Issue>
Your Network Settings have been changed by another application" pops up in the endless loop in the Network preffs pane and the wireless connection between my PB G4 and Apple base station has been interrupted.

It is probably related to the last Security update 2008.

The last security update 2008 for Mac OS X 10.4.x (11) lead to the never ending loop of Pop-up message saying "Your network settings have been changed by another application" in the network preferences pane plus even worse it lead to disabling of WiFi connection between the Powerbook and the Apple wireless base station.

My solution:
Step 1
Delete the following:
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
I deleted the following files

This will get you rid of the pop up window.

Step 2:
Clean up the keychain with the Keychain Access utility in the Utility folder. I mean completely erase all YOUR passwords and keys. (that was what I'd done)

Tis will re-access the Apple WiFi base station.
You will have to re-save your passwords to the keychain database upon the prompt later.

After those steps, all work fine at least for me.
Thanks also to Macfixit.com and macosxhnts.com
No guarantees anyway.
Good luck and happy computing. Rob

Excellent advice Robert. Its cured my network setting dialogue loop.

Unfortunately I now have a problem with the fonts both Safari and Firefox are using to display secure web pages. All of these type of pages are displaying mainly in a comic style font after following your tip of removing the

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

files.

It's only secure pages that are displaying this characteristic, any ideas how to reset the fonts used in secure pages?

Managed to get to the bottom of the font problem. It was a corrupt postscript font - Font Book unearthed - selected all fonts in Font Book and chose 'Validate Fonts' - from the File menu (also ran resolve duplicates from the edit menu). very strange how removing those pref files triggered or exposed this problem...? Hope this helps anyone else who comes across the same issue