Wifi problems after 4.4 KitKat update After updating to 4.4 all of my Nexus devices (4, 7 &amp; 10) have problems with wifi, they all worked fine before the update. 
After some idle time they lose the wifi connection and it can only be reactivated after restarting the device. 

The Nexus 7 right now doesn't connect to wifi at all, I can set the wifi switch to 'on' in the settings but it won't even show available wifis (see screenshot). 

Anyone else experience this? Any ideas on how to resolve it? Without wifi the device is pretty much useless. 


Screenshot (click image for larger variant)
I found out what the problem was: on every single device there were 'battery saver' apps installed. The devices are in my workplace, so I'm not the only one who uses them and someone must have installed those apps. 
I didn't care for them until now and they never did any harm, but they somehow must've interferred with the new 4.4 Android. After uninstalling them everything is fine on all devices :)