For the third time in as many days, this time while I was watching a Vimeo video, and at about two minutes into the four minute video, this pops up over the video. Anyone else experiencing this behaviour?

Something to check out...

When in the AirPort Utility, go to Airport Utility Menu --> Preferences. You'll see a window like this:

http://www.ehmac.ca/images/links/airport_utility.png

If you have "Check Airport base stations for problems", the Airport Utility will simply open if a connected base station's light blinks amber. Perhaps the base station is having an intermittent issue?

If you are using AirPlay or streaming lots of video, I find that sometimes an Airport Base Station can occasionally cut out of for a very brief period. Maybe that is happening?

If by chance you have that option selected in the Airport preferences, maybe try disabling it?

Just a shot.

Thanks ehMax, "monitor airport base stations for problems' was checked by default. I unchecked it and will see if that eliminates the issue. I suspect the 'problem' is the old Express labelled basement.

Thanks ehMax, "monitor airport base stations for problems' was checked by default. I unchecked it and will see if that eliminates the issue. I suspect the 'problem' is the old Express labelled basement.

The 'old' Express is dead, based on your screenshot - hence no green light on its status. I'd check the Express physically to see if it has any active light - green, amber or no light at all.

The 'old' Express is dead, based on your screenshot - hence no green light on its status. I'd check the Express physically to see if it has any active light - green, amber or no light at all.

Ah, good catch, just noticed that. Yeah, that's probably what's making the Utility open up.

The 'old' Express is dead, based on your screenshot - hence no green light on its status. I'd check the Express physically to see if it has any active light - green, amber or no light at all.

The trouble it seems is that the 'old' express in the basement can only be accessed with Airport Utility 5.6. It currently has a green light on that I can see physically. When checked with AU 5.6 it also shows as OK with a green light (See below). And of course, the ML version of AU shows it as down. That's weird.

have to tried to see if it requires any new firmware upgrades?

My problem appears to be solved, so this is by way of update. I double checked the Basement Express and it had a green light. I also had an extra Express that I used to use in the motor home that never really delivered much boost to the network at about 100 feet away and having to pass through the walls of the house, both walls of the detached garage out back, then through the wall of the motor home itself. Upgrading to the new Airport Extreme made a big difference, but I never could get internet speeds above 5 mb/s.

I reset and reprogrammed both of the old Express units and put them at either end of the basement in our home. I bought a new version Express and put it in the motor home, called 'Don's Airport Express'. What a difference. I now get full 15 mb/s speeds in the motor home 100 feet away , the same as in the house.

The two older Express units, now called 'Basement (Old)' and 'Basement (Newer)' are set up for Airplay for our daughter who has a suite down there.

A bit of a hassle, but the end result was well worth it.

I still cannot see the two 'Basement Expresses" as active with Airport Utility 6.1. I have to use Airport Utility 5.6, but both Apps show green lights active all the way around as you can see below.

I still cannot see the two 'Basement Expresses" as active with Airport Utility 6.1. I have to use Airport Utility 5.6, but both Apps show green lights active all the way around as you can see below.

AirPort Utility 6.1 is incompatible with older Express and Base Stations. Using 5.6 is the correct way to manage them.

The AirPort Utility 5.6 for Lion (as opposed to 5.6.1 for Snow Leopard) I have read will not install in Mountain Lion, but may work if you upgraded from Lion to ML; I haven't tried yet myself.

but i have no problem managing my AE with airport utility 6.1..
mine's the ABGN 5ghz capable AE back from 2007 or 2008.

but i have no problem managing my AE with airport utility 6.1..
mine's the ABGN 5ghz capable AE back from 2007 or 2008.

Likely because you are not using an Apple Extreme base station would be my guess.

but i have no problem managing my AE with airport utility 6.1..
mine's the ABGN 5ghz capable AE back from 2007 or 2008.

So, the incompatibility is with AEs is older than yours.

Likely because you are not using an Apple Extreme base station would be my guess.

The AEBS has no impact.

My two older Express units are from perhaps 2005 and 2009 or somewhere in that date period. If IllusionX can see his on ML Airport Utility, why can't I? Or maybe he isn't on ML?

AirPort Utility 6.1 does not support any AE or AEBS that is 802.11g or earlier, it has to support 802.11 Draft N at least.

AE, June 2004 - March 2008, 802.11b/g Not Supported
AE, March 2008 – June 2012 802.11a/b/g/Draft N Supported
AE, June 2012 – Present, 802.11a/b/g/n Supported