I had the same problems as you all describe on three devices (one 4S and two ipod touches) I upgraded to IOS 6.
I tried all the fixes suggested, resetting networks settings, restarting the AP etc to no avail.
In the end my problems ended when I upgraded my Cisco WAP4410N access point to the latest firmware. All three devices have been stable for more than 24 hours now, before they wouldn't stay connected for more than an hour or so max.
Wireless itunes sync however is still not working but that's a minor inconvenience.
Good luck to all you having problems with this, give upgrading your Access Point/Router a try, hopefully that will help you as well.
Just to add one more victim of iOS 6 update on iPhone 4s:
I really tried EVERYTHING I could find in this forum and in the web to fix the problem but my iPhone 4S (a quite new one) is still not able to stay connected to my router (a German Telekom Speedport W 722 Type B). It continues switching betwenn Wifi and 3G. As soon as I am connected to the router via Wifi I am able to download emails or get acces to the internet until the connection breaks, usually after some seconds. I had iOS 5.1.1 installed before on my 4S without any problems.
The crazy thing is that I installed iOS 6 on my old iPhone 3GS and iPad 2 (Wifi only) without any problems. Both work fine with my router.
I will have an appointment with my apple store here in Hamburg this afternoon, but I do not think that they will have a solution or that an exchange of the iPhone will help.
So, some hours later now and I got a new iPhone 4S in the Apple Store in Hamburg, updated it to iOS 6.0 using iTunes (but did not recover any personal backups from the previous iPhone 4S) and it worked from the very beginning without any problems. No Wifi interruption so far.
My old iPhone 4S was not even able to connect to the free Wifi network in the Apple store. I had the same problems there like at home, an enduring switching between Wifi and 3G and it took a while before I was able to connect to the Apple network at all.
A second thing that is interessting was that I had no problems with the passbook app this time. With my old iPhone 4S I was not able to connect to the app store within the Passbook app. There always an error appeared, that there was no connection to the itunes store or something like this. I only could solve this problem by changing the date to one year in the future manually, starting the app (which worked now properly) and then switching back to "Set automatically" (Date & Time). This solution for the Passbook app was posted in a lot of web pages. However, as I mentioned before I did not experience this problem with my new iPhone 4S after upgrading to iOS 6.
I have a working work-around here.
1st, you need a desktop/notebook that is wifi enabled.
2nd, download and install "connectify lite" here is the link. http://www.connectify.me/download-lite/?refid=
3rd, start the hotspot from your laptop/notebook connect then your problematic iDevice to your "connectify hotspot" from your PC
works for me. while waiting for a fix from apple!
please reply to me if it works/failed.
hope it helps!!!
I few others have touched on firmware issues with the WG102 - I have downgraded from 5.0.3 to 5.0.1. Have 3 4S in my house and all of them were mitigated with the F/W downgrade of the WG102 access point. Have tried dozens of other things trying to correct this with no success. Thankyou who ever found this!
I have several problems with iphone 3GS and ios6 with wifi connection.
I try everything, more times, without success,
and on the same network all other device , 2 other iphone works great.
The problem come from my old acces-point !!! The ios6 din't like it !!!
By other friends was the update from the router. ios 6 works different !
Change it, buy a new one, and everything will be OK !!!
I have read that others have trouble connecting.. my issue is that the wifi toggle doesn't work at all. People keep trying to give the fix of "turning off wifi then hard reset then turn it back on" or some other series of turning off apps or "do not disturb" and then re-turning on wifi..
THE WIFI TOGGLE IS GREYED OUT COMPLETELY AND YOU CAN NOT EVEN TURN IT ON AT ALL.
Wifi is off when it rebooted:--->
Go to settings to turn it on but... well, can't turn it on because the toggle is greyed out completely and won't move:--->
Before someone says to take it in to the store.... unfortunately I live in Montana. My nearest store is in WASHINGTON..
I bought this phone not even 4 months ago.
ANYONE have any fixes besides reverting (can I even do that) to the older OS?
I had the same problem with my iPhone and iOS 6.
I try everything possible. I fix this problem, by controlling
for update for the router, and then I find out that the device
works great in other wireless. Try to login in a wifi of a McDonald
and if it works, buy a new access point . I do that and now
works grat !!!