Yosemite (OS X 10.10) killed my WiFi :(

For the record, I had the exact same issues as above. Wireless would drop all the time, 2/3 of pings dropped and the wireless would disconnect and reconnect every few minutes. I used NetSpot to monitor the connections and there was never more than 10 minutes of consistent connection.

Luckily I performed a time machine backup just before upgrading and I have restored back to Mavericks. Problem gone, wireless is now stable and I can now get back online.

This IS a problem with Yosemite that should have been identified by apple well before release, especially considering the number of people who had reported similar issues on the beta.

Im sticking with Mavericks for the time being as this bug turns my Mid 2014 13" MBP into a door stop.

see here:

OSX Yosemite Wifi issues

You aren't the only one.

Same issue here with my iMac27"

Wifi goes ok, until sleep o restart.

Then get stuck "looking for network..."

Tried everything posted here with no luck.

I have to go wifi / open network preferences / diagnostics / continue / continue / always allow (acces keychain) and then works fine... til new sleep/restart/reboot

Even tried removing/deleting all keychains, all certificates, all passwords,rebooting router ... (router/wifi goes ok in all other devices)

Good News,

tried this:

mamaricciOct 18, 2014 12:16 AM Re: OSX Yosemite Wifi issues
Re: OSX Yosemite Wifi issuesin response to cagperez

I just tried something, which so far seems to be working. Go in to your Keychain access - System. Find your wireless network - double click. There are two tabs, Attributes & Access Control. Go into the Access Control and check "allow all applications to access this item". Mine was defaulted on confirm before allowing access, which I think was knocking me off every time I tried to do anything.

I'm not sure, but this is the first 10 minute period I haven't been knocked off since upgrading last night. Good luck!

Great!
Works for me after many hours of searching the solution.

Thanks!

Tried first three and still no luck 😟

seriously hoping Apple releases an update to fix the bugs soon

Had a panic call from a friend who lost all wifi functionality after Yosemite upgrade.

iPads and iPhone on same network still functioned normally.

GalagBasha solution worked for them. Laptop back running.

Anyone who just upgraded to Yoesemite 10.10 and is connecting to a router / gateway that is 802.11ac enabled, be aware that there is an issue if your gateway is using the channel 149 or above.

To get around this issue (which is not ideal), you will need to connect to your router/gateway either using your 2.4GHz frequency or use an ethernet connection.

Once you have done that, log into the gateway/router interface and change your 5GHz Wi-Fi channel to any channel BELOW "channel 149"

hope this will help

I also opened another thread without seeing this thread here:

Re: Mac OS 10.10 Wi-Fi 802.11ac, Upper channel 149-165 issues

Macbook Air mid 2013 - wifi does not work right after the system start or awake from sleep.

Connection icon indicates that it is connected, but in reality nothing happens, it cannot transfer any data at all.

To solve this, I need to switch networks or switch it off then back on.

Indeed, wifi is AC 5 GHz, but channel is 36

Thank you so much JamieAscot.

It works. this is the only way that works very well:

Guys, I have a Macbook 2008 Unibody, upgrading to Yosemite killed my wifi too. Cannot turn it on at all, and it was stuck "off".

None of the solutions so far in thread worked (clearing PRAM, deleting configuration folders etc. Did nothing).

But I fixed it, heres how:

1. Open Network Preferences, click once on the WiFi adapter in the list there on the left. Then click the little cog icon at the bottom and select "Make Service Inactive". Click APPLY.

2. Then click on the WiFi in the same list there again, and then click the - button to delete it. Click APPLY.

3. Reboot the Mac.

4. Once rebooted, go back into the Network Prefs, and under the network adapter list click the + button, and then in the dropdown list (which is probably showing Bluetooth by default) select WiFi. For the name field, change it from WiFi to WiFi2. It's important you add something to the name here (I've just suggested to add a number 2), or else it will break again on next reboot. Click APPLY.

You should then have a working WiFi, that survives reboots.

I had the same problem with a 2012 MBP. After a few hours of beating on the machine and the network I ran into a post that turned on a light bulb. A post that said Yosemite had problem with higher channels on the 5Ghz (citation below).

I then Alt clicked the network icon in the top menu bar. I noticed that it was connected to my 1 SSID that contained both my 2.4 and 5 GHz router radios. I was of course connected at 5GHz and channel 161. I then created a separate SSID for the 2.4 radio.

I connected to the 2.4 GHz dedicated SSID and voila "All network sluggishness" is now gone.

This is not perfect, I need to get it working on the faster network but in the mean time I again have a happy wife with a usable MBP.

Good luck

Re: Mac OS 10.10 Wi-Fi 802.11ac, Upper channel 149-165 issues

There is no speed difference between the different frequencies. Speed is determined (a) by the protocol in use (a/b/g/n/ac etc) and (b) the wireless reception. The reception can and will be different for different frequencies (different frequencies reflect differently). 2.4G networks have longer range than 5G networks in free air.

Still doe not explain why Yosemite hinders the wifi from detecting 5G. My iPhone and iPad have no problem. Definitely a Yosemite problem as Maverick was just fine on th same machine.

This fixed this for me... with an added router reboot. Thanks everyone!

Thank you so much JamieAscot.

It works. this is the only way that works very well:

Guys, I have a Macbook 2008 Unibody, upgrading to Yosemite killed my wifi too. Cannot turn it on at all, and it was stuck "off".

None of the solutions so far in thread worked (clearing PRAM, deleting configuration folders etc. Did nothing).

But I fixed it, heres how:

1. Open Network Preferences, click once on the WiFi adapter in the list there on the left. Then click the little cog icon at the bottom and select "Make Service Inactive". Click APPLY.

2. Then click on the WiFi in the same list there again, and then click the - button to delete it. Click APPLY.

3. Reboot the Mac.

4. Once rebooted, go back into the Network Prefs, and under the network adapter list click the + button, and then in the dropdown list (which is probably showing Bluetooth by default) select WiFi. For the name field, change it from WiFi to WiFi2. It's important you add something to the name here (I've just suggested to add a number 2), or else it will break again on next reboot. Click APPLY.

You should then have a working WiFi, that survives reboots.

Finder > Air Drop > (set) Allow me to be discovered by: (to) No One

I still see this issue even on my 2.4Ghz network.