Yosemite (OS X 10.10) killed my WiFi :(

Yep same issue MBP (Late 2008) worked fine on Mavericks. Also I tried all the suggestions and still no luck. I turned off router and reset it and nothing. Hard wire works the way it should and surprisingly enough it will not connect to my router but it will connect when I hotspot my iPhone. I am going to downgrade my mac back to Mavericks until Apple can resolve these issues.

I didn't delete the Wi-Fi tab but just leaving it inactive and duplicated a new one. It worked for my iMac late 2013. Thanks JamieAscot!

Rudifromdonvale's solution worked for me. I had tried PRAM reset and removing SystemConfiguration folder with no luck.

Using 'Join Other Network...', then manually entering the network name and password seemed to do the trick.

This ended up failing :-(

I have tried all solutions on this thread and within 12 hours my wireless still fails.

The only solution I have is just to disable/enable wi-fi as it happens.

Same here on my New Mac Pro. Wi-FI turns off daily and I cannot turn it back on. I have to re-boot. Come on Apple! It is your hardware and OS, let's get an update with a fix for this annoying issue asap!

I called tech support and tried three fixes with no result. Tried new location. No help. I don't want to delete 10 years of wifi passwords just to fix this. And some say that won't work either. I can't believe no one at Apple recognized this problem and that it is not fixed yet.

I "think" this worked for me but if it did then it only worked for one of my accounts ... mine, which is the admin account.

However, is was still painfully slow on my son's account - its his machine. After a bit of messing around I think I nailed the second problem down to NetNanny. NN is now turned off and he is now happily playing the Steam game that drove the upgrade to Yosemite in the first place. The machine is a 2011 iMAC upgrading from Mountain Lion not Mavericks which is why he had to upgrade.

If you have any 3rd party software doing any network filtering then it may be advisable to test with it turned off and see if that helps.

It may also therefore be worth testing with a new, clean account.

Here are the most prevalent solutions available:

1. Creating a New Wi-Fi Service (this solution worked for me!)
   • Copy and paste these instructions, because you'll be disconnected from the Internet and you'll need to reboot.
   • Go into your Network Preferences > Select Wi-Fi Service (in the list in the left column) > Click on the options (cog icon) > Select "Make Service Inactive" > Select Apply.
   • Select the same Wi-Fi Service > Delete It ( – ). Reboot.
   • Return to Network Preferences > Create a New Service ( + ).
   • Inside the prompt select Wi-Fi under Interface, name the Service Name something other than Wi-Fi. (I named mine Wi-Fi2. Apparently if you retain the previous Wi-Fi name the WiFi dropping will return on reboot.) > Click Create.
   • Click Apply.
2. Delete and Reconnect to your Preferred Network

   Go into your Network Preferences > Advanced > Select Your WiFi Network and Delete It ( – ). Reconnect to it.

3. Delete Bluetooth.plist

   Finder > Go (on your toolbar) > Computer > HD > Library > Preferences > Delete your Bluetooth.plist. Reboot.

4. Delete SystemConfiguration

   Finder > Go (on your toolbar) > Computer > HD > Library > Preferences > Delete your SystemConfiguration. Reboot.

5. Reset PRAM

   Reset your PRAM (Haven't tried it myself so I don't feel right instructing others how to do it, sorry!).

Sorry if this isn't as comprehensive or clear as you may need. If you need more clarification, I'll keep this thread open and check periodically. Thanks Rudifromdonvale for mentioning the first solution!

Good luck!

First one worked for me. Thanks so much.

So my wifi also kept dropping after upgrading to Yosemite. I tried to delete the Systemconfig files too. But that didn't really work.

I ran a diagnostic using the provided mac tool and the report says my wifi is being used by multiple sources and suggested to use 5GHz wifi instead of the 2.4GHz. I have a Netgear router that produces both signals, so I switch to the 5GHz and wifi stays on now.

This solution seems to have worked on my 2011 iMac. Thank you JamieAscot!

First option worked for me! Thanks!

None of the suggestions have worked for me so far. What seems to work though is to disable the 5 GHz frequency on the wifi router. Connecting to 2,4 GHz (b/g/n) seems to work well and no connection drops so far. Please try this as well and report back here.