Airport Express 1st Generation - can join but not extend network

Thanks for the info. Which device is your "main" router?

In order to "extend" the network, an AirPort Express must connect directly to the "main" router......not to another AirPort that might already be configured to "Extend a wireless network".

This would mean that the 1st Gen Express must be located closer to the "main" AirPort than it is to any other AirPort.....so that the Express will pick up a stronger signal from the "main" AirPort than any other AirPort on the network.

Unfortunately, Apple does not provide these types of details in the setup guides for the products.

If you do want to try to configure the 1st Gen Express to "extend" the network, you cannot simply change the settings on the Express......you have to reset the Express back to factory default settings and then set it up again. Post back if you need more help with this.

Finally, you might not be aware that when you set up an AirPort to "extend" the network, the maximum speed on the entire network will be cut by at least half and possibly more. So, while you might have a "bigger" network, you will also have a significantly slower network.

Let's first confirm that you really do have a 1st Generation AirPort Express. Look on the side of the device for the model number......hard to see with gray lettering on a white background.....so you may need good lighting and/or reading glasses to see the model number.

The 1st Gen AirPort Express is model number A1264. Is that the model number that you see?

If you have the A1084 or A1088 version of the Express, those models do not have a setting to "Extend a wireless network", so they cannot be used for that purpose.

Next check would be to confirm that your "main" router is also another Apple AirPort product, since the A1264 version of the Express can only "extend" a Wi-Fi network that is being provided by another "main" AirPort router.....an AirPort Extreme, AirPort Time Capsule, or another AirPort Express.

If you do have another Apple AirPort router acting as the "main" router and you do have an A1264 version of the Express, it still may not be possible to configure the Express to "Extend a wireless network" depending on where the Express is located. Things can get complicated, in other words, because the Express will need to be able to pick up stronger signal from the "main" AirPort than it does from any other AirPorts that might already be set up to "Extend a wireless network".