Why won't AirPort Utility let me extend my network with AirPort Express?

Connect to the WiFi network of the new Express. This can be found at the AirPort fan on the top right hand corner of your Mac.

All of the previous forums I've seen say to reset both routers and "set up manually" and select the box that says "allow this network to be extended". When I go to setup there is no option for either of these.

You are looking at instructions that apply to Snow Leopard and earlier operating sysems. You are using Lion or Mountain Lion.

Hold in the reset button on the Express that you want to use to extend for 9-10 seconds and release.

Close AirPort Utility if if it open.

As edex67 notes above, click the fan shaped AirPort icon at the top of the screen and look for a listing of New AirPort Base Station. Just below that, click directly on AirPort Express.

AirPort Setup will open automatically and take a minute to analyze the network, then tell you that the Express will be configured to "extend" the network.

Enter a device name that you want to use for the Express and click Next

AirPort Setup will take a minute to configure things. When you see the message of Setup Complete, click Done.

You are done, other than locating the Express approximately half way between your "main" Express and the area that needs more wireless coverage.

Look on the side of the Express for the model number. You need to see A1264 there.

If you have A1088 or A1084, these are older "pre-generation" versions of the Express that do not have the ability to "extend a wireless network".

Of course, you can extend even with A1088 models by using an Ethernet cable or Powerline adapters. To install the older version of AirPort Utility:

http://frank.is/mountain-lion-and-the-old-airport-utility/

Then you can use bridge mode to make them extend. However as Bob Timmons states they can't extend wirelessly.

Ethernet cable would be first choice in terms of performance or use a pair of Ethernet powerline adapters to send the signal over the powerlines in your home.

These devices work well for some users, but not for others....so it might be a good idea to understand the store's return policies before you buy.

Here, we are assuming that you have an open port on your modem/router to connect the second AirPort Express.

Would they both have to be the newer model in order to have them "connect" to one another?

I assume that you are asking about wireless connections here.

You would either need two of the A1264 versions if you want them to connect to each other using wireless, or you would need the A1264 model and another "new" AirPort Express, which would be model A1394.

Thanks this helped me a lot! I wanted to extend my Wi-Fi network, but I couldn't figure out how. Now (thanks to you) I have it all set up!

WEll, it could before mavericks I think. my a1088 extended my wifi network for playing music through my stereo rack until recently in yosemite, until I had to create a new network from my Apple extreme base station, so now it is impossiblemto configurate the a1088 express, I get the same dialogs as others have mentioned here...

You need a newer version of the AirPort Express if you want to be able to use newer Mac operating system to administer the AirPort Express.

Apple dropped support of the older AirPorts when they introduced Lion (10.7.3) a few years ago.