Since I've had my iMac I've noticed that my wifi network locks up a few times a week, it is always fixed by turning off the wifi on the iMac, then turning it back on again.

The network shouldn't be over loaded, it's a Time Capsule with iMac, iPhone, Macbook and Apple TV connected, surely these should all play together nicely!

I've checked and the Time Capsule is at the latest firmware level (7.5.2), so not sure what the next step is.

[edit] iMac is current model 21.5" i3, OSX is at 10.6.6 and software update says everything is up to date.

To clear up unstable the wifi connection always appears to be connected, but if I'm using the iMac I can't view websites, there have also been times where the Airplay streaming has just stopped, so it seems to be the whole network.

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    Which (exact) model of iMac do you have? What version of OS X is installed?
    – Ben Wyatt
    Commented Feb 3, 2011 at 16:02
  • 1
    Are all Software Updates installed? It may be a driver issue that was resolved via update. Commented Feb 3, 2011 at 16:34
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    When you say wifi becomes unstable do you mean for all devices connected to it or just for the iMac itself? Also, when you say unstable what do you mean? Does signal drop out on WiFi? Does signal remain good but you can't get to websites? You need to be more specific. Commented Feb 3, 2011 at 18:17

1 Answer 1


OK well if your problem affects internal traffic (streaming AirPlay) and external traffic (website access) then that points the finger at your Time Capsule. The fact that you've only noticed this since you connected your new iMac might be a red herring but may also be a hint at the cause. I'd start with pinging the time capsule and see if you have periods where you can't ping it. So open Network Utility > Ping and enter the IP address of the time capsule (probably and set it to ping an unlimited amount of times, you'll see output like that below:

Ping has started…

PING ( 56 data bytes
64 bytes from icmp_seq=0 ttl=64 time=1.197 ms
64 bytes from icmp_seq=1 ttl=64 time=1.158 ms
64 bytes from icmp_seq=2 ttl=64 time=0.996 ms
64 bytes from icmp_seq=3 ttl=64 time=0.970 ms
64 bytes from icmp_seq=4 ttl=64 time=1.103 ms

This, in case you don't know, is just sending a packet to the IP address of your time capsule and the time=xxxx on the right is a measure of how long it took to get a response. Now, if something is happening to slow down the network response time, you'll see it here. As you can see there is very small fluctuations (the units are milliseconds) in the response time but you'll be looking for larger differences, such as 1000ms or even dropped packets. Obviously this is only useful if you're seeing the issue every few minutes rather than once a day. Once you prove that you have captured an issue, try the same thing while plugged directly into the time capsule by cable. If you get similar symptoms then I'd point the finger at the router. See how you get on with that and I'll update the answer when you come back if I can suggest some other steps. Good luck!

  • Thanks, it's more once a day, so I'll try the ping when it happens again. You're probably right about the red herring, as not only did I get the Apple TV at the same time (although it has happened with this switched off) I Time Capsule update was actually a week before I got the iMac...
    – LC1983
    Commented Feb 4, 2011 at 9:35
  • It happened again, but the ping times are the same in this state.
    – LC1983
    Commented Feb 5, 2011 at 10:15
  • Were the pings running while you experienced the slowdown? Or did you run them afterwards? Commented Feb 5, 2011 at 10:21
  • I ran them during.
    – LC1983
    Commented Feb 5, 2011 at 21:56
  • OK, so then there was no slowdown on your WiFi. In that case it points the finger back at your Mac if that's what you were using when you saw a slowdown. It takes the network out of it to be honest because you can be pretty sure that with no increase in response time, there's no problem with your WiFi. Commented Feb 5, 2011 at 22:02

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