There seems to be much confusion about what a 1st Generation AirPort Expess might be.
Check the label on the side of the Express for the Model No.
A1264 is a 1st Generation Express
A1084 or A1088 is an older version of the Express, which did not have a Generation designation. AirPort Utility in Mountain Lion does not support the A1084 or A1088 Express versions.
Which Express do you have?
I'm having the same problem. Mine airport express is A1264. I have recently installed Mountain Lion and I can't see the airport express in Airport Utility (v. 6.1). Not sure if it disappeared imediately after installing Mountain Lion or not, because I only use the Express for streaming music to my stereo and I haven't tried it recently.
I tried connecting the Airport Express with an ethernet cable and that does not help. The light on the Express is solid Green.
Any suggestions would be appreciated.
Hi guys, recently had the same issue. You require an older version of Airport Utility to configure the older Airport Express. It can be found here.
http://www.google.com/url?sa=t&rct=j&q=airport%20utility%205.6%20for%20lion&sour ce=web&cd=1&ved=0CFMQFjAA&url=http%3A%2F%2Fsupport.apple.com%2Fkb%2FDL1482&ei=Ip MBUPLwLoq42wW4puXMBA&usg=AFQjCNGOFUPMM0ZjsKeyj5CcL2oe9Eaf7A
Hi, thanks for the link.
Apparently Airport Utility 5.6 is not compatable with OS X Mountain Lion, and further is only required for A108X models of the Airport Express.
It turns out that restarting my router and the computer solved the problem. Should have tried that first... I really should have known better.
the exception being the newest Airport Express.
You will get a warning message if you try to configure the "new" Express using AirPort Utility 5.6, but if you click Continue, it will work just fine.
You do also have the option to intall AirPort Utility 5.6.1 on Mountain Lion if you don't want to see the warning message when you configure the "new" Express.