Q: AirPort base station not seen or "An unexpected error occurred" appears in AirPort Utility 6.3 - It did the above steps and cannot get airport utility to allow access to the Airport extreme in order to reconfigure please help

Mavericks is a mess.

Make sure that you have configured iPv6 to Link Local for both Ethernet and WiFi on the Mac

Have you power cycled the entire network?  If not, power off the entire network...all devices in any order that you want. Then start the modem first, and let it run a minute. Then, start the next device connected to the modem and let it run a minute. Keep starting devices one at a time about a minute apart until everything is powered back up. Then, try again.

What other troubleshooting steps have you performed?

If all else fails try connecting an Ethernet cable from the Mac to one of the LAN <-> ports on the AirPort Extreme. Power off the Mac and Extreme and power back up and try again.

I assume that you have tried to hard reset the AirPort Extreme by holding in the reset button for 10 seconds on the AirPort, then releasing and allowing a full minute for the AirPort to restart.

Can you try an iPhone, iPad, another Mac?

If another device can setup the AirPort Extreme, then your AirPort Extreme is OK. If no other devices can set up the AirPort Extreme, then you have to start to suspect a possible defective AirPort Extreme.

Otherwise, the next step....which I have had to do to "fix" the Mac......is to completely reinstall Mavericks....with no guarantee of success.....so be sure to check with Apple Support before you do this.

Not really solved.....Mavericks is still a mess. 

I'm in a frustrating predicament with this error, so if folks have any suggestions, that would be greatly appreciated...

A few days ago my internet stopped working as best i know out of the blue (3rd gen Airport Extreme with a couple iPhones, iPad, Apple TV's, Mac's (one with Mavericks) on it).  In trying to fix it, I powered down everything and reset the router.  When the router is initializing (seen through the Airport utility), the internet starts working again on the Mac in which I'm running the Airport utility. (a browser in background loads a previously unloadable webpage).  I'm then left with a screen where the Airport utility is waiting for me to enter set-up info:

If I leave the Airport Utility in this state and don't hit next, my internet works fine on my Mac.  If I set-up this info, however, my internet no longer works (in Airport Utility the Internet globe has a orange circle saying internet disconnected) and I get a screen saying "An unexpected error occured.  Try again."  I've tried toggling a number of router settings, restarting the router, but nothing seems to fix it.

I've taken the router to Apple, where they were able to create a network fine with the router.  I also bought a new AE router, and tried an old AE express router, but all attempts get the same error.  I've also tried using the iOS Airport utility, but that doesn't seem to help.  I've tried the older version (5.6) of Airport Utility run on a non-Mavericks Mac, but that didn't help.

I had a ISP technician come out, but they basically said the plug (we don't have a modem, but just a ethernet plug in our apartment)  in which you're getting the internet from us is working, and it's your router.  They're diagnostics said the router is 'throwing off a bunch of errors.'  That being said, they've confirmed the setting on the AE are okay (as far as they know...).

Any thoughts here?  I'm not especially network-proficient, but searching around has pointed me to potential issues with mavericks, IPv6, and the latest version of the Airport Utility. 

I'm desperate - please help!

Much thanks in advance.

I've taken the router to Apple, where they were able to create a network fine with the router.

Did the Apple folks use your Mac to do this, or theirs?

Have you tried to configure the AirPort Extreme using an iPad or iPhone?

Did you perform a full factory default reset on the AirPort Extreme as follows?

Power off the AirPort Extreme

Wait a few minutes

Hold in the reset button first, and keep holding it in firmly for an additional seconds while you simultaneously plug the power back into the AirPort Extreme

Release the reset button after the hold period

Allow a full minute for the AirPort Extreme to restart to a slow, blinking amber light?

(If you tried to reset the AirPort Exteme simply by holding in the reset button when the AirPort was already powered on.....this does not completely reset all of the settings on the device)

Much thanks for the response!  Fortunately, I've finally gotten the router to work...looks like the issue was related to IPv6 settings.  I'm not on Comcast, but I followed the instructions from this article, and now the router works:

http://mydeviceinfo.comcast.net/download.php?file_id=35

Not sure if apple reads these...but I had the same issue.

Reset my network password and the express that had been extending the network would not reconnect to the network.

Had been trying to use airport utility on both my ipad and my iMac and could  kept getting the "unexpected error..." when trying to bring my express back on to extend my time capsule network.

Read this post and remembered you have to go through settings>wireless on ipad to configure a new express. (Totally counter-intuitive by the way...why you can't do this through the utility on ipad, and rather have to go through settings is beyond me.)

In any case...set-up with the ipad worked.

Thx,

Changing iPv6 to Link Local appears to have solved my issue.  Wish this was clearer so I would not have watsed many hours which I will never get back

After reading SO MANY different solutions this is all I needed to get it to work. Thanks so much Daniel.

This worked for me. My 1 year old airport express stopped extending my network and after numerous hard resets, I couldn't get the airport utility on the iMac to make the express work again. I was about ready to throw in the towel and call it a band transmitter in the express and purchase another one. This fine instruction worked. Is it just me or are apple products becoming just as problematic and quirky as PC?

I'm not sure which 'fine instruction' it was that worked, but I've tried the 'link local' and 'use an iPad' together, and I still get 'waiting for hi-fi' (that's the name I set for my airport express, which our hi-fi is plugged into), and then after a few minutes 'unexpected error' comes up again.

Thanks.  After hours of research, trial and error.  This was indeed the solution!