My devices all work (Airport Extreme and Airport Express), but Airport Utility says "Device not found".

Try again but use a full factory reset.. on yosemite it is really important to keep those names short.

Factory reset universal

Power off the AE.. ie pull the power cord or power off at the wall.. wait 10sec.. hold in the reset button.. be gentle.. power on again still holding in reset.. and keep holding it in for another 10sec. You may need some help as it is hard to both hold in reset and apply power. It will show success by rapidly blinking the front led. Release the reset.. and wait a couple of min for the AE to reset and come back with factory settings. If the front LED doesn’t blink rapidly you missed it and simply try again. The reset is fairly fragile in these.. press it so you feel it just click and no more.. I have seen people bend the lever or even break it. I use a toothpick as tool.

Then redo the setup from the computer with Yosemite.

1. Use very short names.. NOT APPLE RECOMMENDED names. No spaces and pure alphanumerics.

eg AEgen5 and AEwifi for basestation and wireless respectively.

Even better if the issue is more wireless use AE24ghz and AE5ghz with fixed channels as this also seems to help stop the nonsense.

2. Use all passwords that also comply but can be a bit longer. ie 8-20 characters mixed case and numbers.. no non-alphanumerics.

3. Ensure the AE always takes the same IP address.. this is not a problem for you as the cable modem SB5102 has no router.

4. Check your share name on the computer is not changing.. make sure it also complies with the above.. short no spaces and pure alphanumeric..

5. Make sure IPv6 is set to link-local only in the computer. For example wireless open the network preferences, wireless and advanced / TCP/IP.. and fix the IPv6. to link-local only.

There is a lot more jiggery pokery you can try but the above is a good start.. if you find it still unreliable.. don't be surprised.

Post more details of the actual setup of the extreme and modem it is connected to.

Airport Utility just started telling me that my Time Capsule could not be found, with the yellow alarm triangle. However, everything was working perfectly, re internet and Time Machine Backups. The Time Capsule showed green the whole time. I later checked with my laptop and it showed a green dot next to the Time Capsule icon and let me open up the edit function. When I went back to my iMac it was now also green. So something is fishy with the Airport Utility (6.3.5). For some reason is thinks the time capsule is not connected when it in fact is.

So something is fishy with the Airport Utility (6.3.5). For some reason is thinks the time capsule is not connected when it in fact is.

There are a lot of bugs in Yosemite, which Apple has yet to solve despite 3 major updates to Yosemite.

Did you find a solution? Because i've got the same problem and it's getting on my nerves.

It started as soon as i upgraded to El Capitan.

I've got the same set up. I stream audio to the airport express, and sometimes it suddenly says it is "not connected". While in fact it is connected. Other devices can stream audio to it just fine. When i open airport utility on my iPhone it says everythings fine.

But when i open airport utility on my mac -at the same time- it says "device not found".

Turning Wifi on and off on my mac solves it for a while, for both the audio and the airport utility. But the it comes back. Sometimes after 5 minutes, sometimes after a few days, but it always %%$#%@ comes back.

I tried everything i can think off. Reset the entire network. Deleted settings on my mac. PRAM / SMC resets. Turning off ip6. Fixed channels.

Any help would be very much appreciated.

Using those short names.. and manually mounting the TC in finder can help. Also if it is in bridge.. I strongly recommend you have a go with this setup.

Re: airport time capsule keeps disconnecting

If you need help tell me what step is not clear and give me some screenshots of the setup.

I will need to know what modem router you are using and how you have that setup as well.

Thanks a lot!!

I'll give it a go.

Not sure what u mean by manually mounting (the airport extreme in my case) in finder.

This is my set-up in normal condition:

It is setup like this: via DHCP, WPA2 personal, IPv6: automatic, ipv6 mode: native.

I created a guest network (also WPA2)

Channel is on automatic

Routermode DHCP and NAT

Airport express: static IP, WPA 2, Bridge mode/extending range

While using these settings the network has been quite stable the past week. Only had a drop-out today.

If you need to know anything else, just let me know.

Ahhhh... What happened to "it just works" ? ;-)

Thanks again!

Your names are still not what I want.. I mean short like 10 characters and no spaces.

ie call the AIrport Extreme.. AE

And call the Airport Express AEx

Use name like AEwifi for the wireless.

If it lasted a week that is not too bad.. apple stuff is not as reliable as it was.. uptime on extend wireless are about that in my experience.

"Your names are still not what I want.. I mean short like 10 characters and no spaces."

The screenshot was from before the reset.

"If it lasted a week that is not too bad.. apple stuff is not as reliable as it was.. uptime on extend wireless are about that in my experience".

But it lasted for more than a year on standard settings! Besides it's not the express that's down, it's my iMac that can't reach it.

My iPhone can stream audio and acces the internet just fine. From my phones airport utility i can get to the settings, while my iMac says "connection lost". And it's only a few feet away.

I am beginning to suspect El Capitan has something to do with it.

Anyway, i really appreciate your help! If you have any other ideas, please shoot.

In the meantime we'll see if it will be stable with the shorter names.

Thanks again!!

Trial it for a while..

The OS should always be clean installed.. if you upgrade installed expect issues.. There is no OS in the world in my experience that is reliable in handling upgrade installs.. I have much less issues than most people because I simply never believe in the fast easy approach. Clean install onto a newly formatted drive.. restore files and settings but apps should be reinstalled.. the more effort you go to .. the better the results.

let's say ur main router has 2 ssids ab1 and ab2 for 2.4ghz and 5ghz respectively. the wireless extender will give out 2 signals of both frequencies. Let's say main router is working in channels 10 and 149. And extender works in channels 10 and 153 Extending ssid ab1.

if ur device running the airport utility is connected to the extenders channel 153, then main router would not be accessible. This cud be ur problem. Plz check and revert.

I guess I am wondering why my main AirPort is using Channel 157 and the Airport Express which is extending the network using Channel 161, allows me to access the main AirPort with no problems at all.

According to your information, my main router would not be accessible from a connection using the AirPort Express. Could you explain why this works for me?

I agree that a clean install is always the best option.

But after upgrading perfectly from mountain lion, to mavericks, to yosemite, i got used to it. And the machine works perfectly otherwise.

I really don't want to do a clean install for loads of reasons. Plexconnect is one of 'm.

Anyway i went back to Yosemite. Because i really start to think El Capitan had something to do with it. Up until now everything is fine.

I'll let you know if the issue returns under Yosemite.

are the 2.4 ghz channels for both the router and extender the same? I'm also assuming the express is on wireless extend and not Ethernet.

according to my hypothesis if ur device using the airport utility is connected to a 2.4ghz channel and both Apple routers use the same 2.4ghz channel then there shud be no problem.

my extender could not even find any signal to extend when both routers had different channels. Eg. 4,149 on main router and 9,161 on wireless extender

Wireless extend. Both AirPorts are using different channels for the 2.4 GHz and 5 GHz settings.

The Main AirPort is using Channel 11 for 2.4 GHz and the extending AirPort is using Channel 6. For 5 GHz, the main AirPort is at 157 and the extender at 161.

Then my hypothesis is wrong. I'll have to tinker with my channels now and see what happens. Thanks for ur response.