MacFixIt Answers

Written by Topher Kessler

MacFixIt Answers is a feature from MacFixIt where our editors answer questions e-mailed to us by our readers. This week we have questions about the system firewall repeatedly asking to allow applications, Safari returning errors about being recognized as Internet Explorer, and network settings being changed by applications.

Question:

MacFixIt reader "Ethel Davies" asks:

"I have recently started to be unable to connect via my favourite
network via airport and receive the message 'Your network settings
have been changed by another application'. This comes up and refuses
to allow me to make any changes, and will not disappear until I use
'force quit'. Rumour has it this problem stems from the latest
security updates for Mac 10.4.11. Can anything be done about this?"

Answer:

Unfortunately, without knowing what application is running and what settings are being changed, it is difficult to pinpoint the problem. However, one thing you can try is setting up a network location in the "Network" system preferences, then add your desired connection options (Airport, Ethernet, and so on) and configure the services accordingly. Be sure to click the lock to prevent further changes to the setting so that if an application tries to change anything, you will be prompted with an authentication request. Additionally, you might consider changing your account to a standard user account rather than an Administrator one, which will prevent these kinds of changes from happening.

Question:

MacFixIt reader "Douglas R. Gwinn" writes:

"When attempting to connect to FACEBOOK using Safari yesterday (I
usually use Firefox) I could not log in saying I was using Internet
Explorer (which doesn't even exist on my machine), and to please use
a supported browser such as Safari, Firefox ...

What's interesting (and why I'm writing) is that on my previous Mac
desktop, when attempting to access Mobile Me from Safari it would say
I was using an unsupported browser and to either use Safari or
Firefox. It didn't seem to matter what version I used. What gives,
and why will some sites, even Apple's, not recognize Safari as
Safari?"

Answer:

Although there is no current version of Internet Explorer for Mac OS X, Web browsers can masquerade as another one through the "User Agent" setting. This can help troubleshoot browser-specific and platform-specific bugs in various code differences the server will send to different operating systems and browsers. If your User Agent setting has been changed to Internet Explorer, then your browser will be identifying itself to Web servers as IE which may confuse sites that do not recognize this browser for the Mac. To change your User Agent, go to the "Develop" menu in Safari (enabled in the "Advanced" section of the Safari preferences) and in the "User Agent" submenu select either "Default" or one of the "Safari" options.

Question:

MacFixIt reader "Chris Tomnia" writes:

"I have an iMac 20" 2.4GHz c2d with OS X 10.5.7 on a home Ethernet
network connected to a Netgear dg834g modem-router.
Everything is working well except for a persistent dialog box asking
if I [accept or deny incoming network connection] popping up each
time I'm starting certain apps, such as Vuze and Jubler and now,
since the latest upgrade to 12.2.0, also Word, Excel and Entourage
(this is now really annoying since I start it many times daily).
My Firewall is set up to 'Set access for specific services and
applications' and the five apps (among others) are set to
'Allow incoming connections'. Why does that prompt keep popping up?
It there a fix for this?"

Answer:

Firewall problems such as these can happen if the firewall preference file has become corrupted and is not properly storing your settings. The first thing to try would be to remove the preference file and restart the system. The file is called "com.apple.alf.plist" and is located in the /Macintosh HD/Library/Preferences/ folder. Delete this file and then restart your computer, booting into Safe Mode by holding the shift key. When in Safe Mode, run a permissions fix with Disk Utility and also clear the system caches with Leopard Cache Cleaner, OnyX, Cache Out, MacDust, MainMenu, and numerous other similar utilities (search for "Cache" at VersionTracker). Doing this will clear cached system settings and ensure files are accessible by the system. After all these tasks have been completed, reboot the system and try setting up your firewall again.

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Topher has been an avid Mac user for the past 10-15 years, and has been a contributing author to MacFixIt for just over a year now. One of his diehard passions has been troubleshooting Mac problems and making the best use of Macs and Apple hardware both for family and friends, as well as in the workplace. He and the newly formed MacFixIt team are hoping to bring enhanced and more personable content to our readers, and keep the MacFixIt community going here at CNET. If you have questions or comments for Topher or the other MacFixIt editors, feel free to contact us at http://www.macfixit.com/contact

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