WiFi goes blind on 10.9 for mid 2012 MBA

Hello folks, hello experts,

this is going to be another thread with issue seen on previous versions of OS X.

I have bought a brand new in a box MacBook Air 11 a week ago, old stock however, mid 2012. It was just a day or two after 10.9 Mavericks came out, so the first thing I did was going to AppStore (over WiFi), made the FW check for the SSD, applied the Update, then (from this part over Ethernet) Upgrade from 10.7.5 to 10.8.5. Right after that Mavericks 10.9.

At home I have added my WiFi network and started to using the thing. Then following issue came out:

After waking from sleep, the WiFi is searching for networks but cannot see ANY.

What I did/tried:

All the possible old tricks (stupid or not) I could find:

- waking the MBA with power button

- keep the Bluetooth turned off

- deleted all preffered networks

- deleted Keychain entries

- moving system cofiguration files !

(- aks about others, I might have forgotten some...)

Nothing helped.

From the On/Off tricks also all possible were tried:

- Wifi

- Sign out

- Restart

- Power

Since the thing was new I had no problem to make fresh new install of 10.9 Mavericks. I did. Did not helped.

The issue is still here.

I have brought the MBA back to the shop, it went to authorized service. They have tried for one day (not sure, may be less) but they could not repeat the issue. They made Apple HW test, all OK. We agreed, when it comes back, they will try longer.

Symptoms:

- When MBA goes to sleep - seems like only the "deeper sleep" with disc unplugged - and then wakes does not see any available networks. WiFi is On and searching. Produces no error, behaves like everything is OK, just there are no networks around.

- Probably it should be not an issue of my router as the MBA does not see any network, not even the ca. 8 newtorks from my neighbours

- There is no 100% cure, the blindness seems to go away randomly. I mean, sometimes one trick helps, sometimes none (On/Off: WiFi, Sign Out, Restart, Power). I cannot tell why it then goes all right.

- My network (from which it goes to sleep) is on TP-LINK router with excellent signal, set up as not broadcasting SSID, Auto channel, WPA2, Auto bgn. I tried using also broadcasting SSID, fixed channel, fixed N.

- I cannot tell if it has a connection to a user, seems like not. There are 2: Administrator and Standard. Looks like the issue might relevant for both. I could update here.

- It does not matter if the MBA is on battery or plugged in.

- This issue never occured on any other device before (Windows PCs, Andorid devices, iPhone, MacBook 2009 - this one was not tested on my network after 10.9 update yet).

Other information:

- All possible updates for 10.9 are installed, including the one from this week.

- No accounts are connected (no mail, no cloud).

- From the installed software, there is TeamViewerQS and Skype - this one was and is not connected, Chrome web browser.

- FireWall is turned on.

Technical information PC:

- MacBook Air 11 inch mid 2012

- 1,7 GHz Intel i5, 4GB 1600 DDR3

- OS X 10.9 - 13A603

- Boot ROM: MBA51.00EF.B02

- SMC: 2.4f19

Technical Information WiFi:

- CoreWLAN: 4.0 (400.45.1)

- CoreWLANKit: 3.0 (300.35)

- Extra menu: 9.0 (900.34)

- Information about system: 9.0 (900.8)

- IO80211 family: 6.0 (600.34)

- Diagnostics: 3.0 (300.37)

- AirPort utilita: 6.3.2 (632.3)

Interfaces:

en0:

- Card Type: AirPort Extreme (0x14E4, 0xE9)

- Firmware version: Broadcom BCM43xx 1.0 (5.106.98.100.22)

- Local: ETSI

- Country: SK

Any other required information or log files could be supplied within my skills (and your navigation), just ask for them.

My personal humble opinion told/tells me follwing:

- At first I thought it was SW issue. That is why I did the clean re-install.

- Afterwards it looked like a HW problem. That is why it went to AD/S.

- Since all HW tests passed OK, I think again it could be only SW issue. The question is now, is it a WiFi firmware issue or OS X 10.9 issue ? Or both...

Any input will be welcomed and highly appreciated. Thank you all in advance !