I think the only surefire 'fix' from what I've seen so far is to drop down to using 802.11 b/g mode, but having just forked out for a brand spanking new a/c router I hardly think this is an acceptable solution.

The problems certainly seem to be worse for using a/c mode than for 802.11n, although I can reproduce the same problem with an N standard router also.

Just to let you know, the only fix that is really working for me now is the SMC reset.

However, I got some problems with bluetooth and wifi as well after a few hours. But after the second try (two days ago) it's working flawlessly!

802.11n is an absolute no-go for me.  When I connect, it's at 802.11g on 2.4GHz network or 802.11a (not ac) on 5GHz networks.  If I put either network in n-only mode, I get an error trying to connect.  The System Information app lists my networks with PHY modes of g and a, respectively.  I've tried everything in this thread from PRAM/SMC resets to deleting .plists to renaming networks and such.  As Hevelius says, when it drops to b/g mode it does connect and it does stay connected.

Oh, and here's the kicker: in Boot Camp on Windows 8.1, it's fine!  Connects at 802.11n speeds on either network, speeds are better, and no drops.  It's absolutely a software problem and all the solutions here are just placebos or temporary band-aids. Apple will have to fix it in software.

My network has been a lot faster and stable for 24 hours now. 

I did the below.

1)

HD -> Library -> Preferences

Rename "SystemConfiguration" to "SystemConfiguration.OLD"

Restart

2)

And then I change the country on my AirPort Extreme.

AirPort Utility -> Wireless -> Wireless Options -> Country

Changed from Austria to my country.

But my hunch is that it was more the restart of the AirPort than the country setting that helped.

I am not sure that it will work perfectly, but is a LOT better than before.

Had the same issue on my 2013 MBA. I "solved" it by deactivating the 5Ghz Band on my Wifi-Base-Stations. By the way, i always got more speed on the 2,4Ghz Band, but maybe this is an issue of my routers.

So far, I´m ready to re-format my mac mini and install Mavericks and keep it running until I see that Apple released a fix for this issue. :/

My mac mini is a litle bit far from my router, so I can´t use a cable to work. I NEED my wifi working fine. :/

Comon Apple.. let´s work!! Listen to your clients, those who pays you for something that.. how do you say? "It just works"?

Comon...

Having the same issues....wifi dropping, dropbox not working, Gmail keeps saying 'unauthorised access' tried.....connection issues.

For me the issue is only when I connect to my 5Ghz band. When I connect to 2.4Ghz, things work as normal, as soon as I turn my 5Ghz band on, My WIFI starts *****.

Hi, Can someone from Apple PLEASE read the comments on 'OS X Yosemite wifi issues' as it is a live problem and needs to be fixed ASAP. I should have left my OS X Maverick.

I had a similar problem where my MAC wont catch the WiFi signal but all other devices running Windows would catch the signal correctly.

I changed the wireless channel to 8 (from Auto) in my WiFi router and it fixed the problem.

I observed this same issue after upgrading.

I have Norton installed on my Mac.  After the upgrade Norton started reporting PortScan attempts.  After turning this off (not my first choice), my problems went away.

For those of you who know Mac much better than i do, this may offer a clue as to the root cause.

Dan'l

It's not only a Yoz issue. It's been around for since before Mvrx. Here's a good new one for ya. My Yoz install after I worked in SLS for a day, upon reboot to the partition that I have Yoz on, I found the install had reverted to the clean install. The two days of setting up Yoz is gone including app installation.

BUT! I got WiFi back on my MBP as a whole, SLS, Mvrx, Yoz after installing Yoz Public Final.

I had the same problem like everybody does. I was losing my connection every 30 seconds and would have to turn off Wi-Fi and then turn it back on in order to have internet connectivity.

But today I bought one used AirPortExtremeBaseStation and it solved the problem.

I think Yosemite can best communicate with apple wifi that's all.

And now apple wifi 5 times faster..... really

Thats a $200 dollar fix. So much for a free upgrade. Apple needs to get it together.

man, I definitely should have checked before updating. add me to the statistic of users whos wifi keeps dropping every 2 minutes. nothing works.