About a week ago, my OSX machine stopped connecting to any WiFi networks automatically. If I open the WiFi menu from the top bar and select the desired network, it connects OK. Also, if I enable "Ask to join new networks" from the Network preferences, it shows the "No preferred networks found" dialog, even though the network is both in the list shown in that window AND in the preferred networks list in Network preferences -> WiFi -> Advanced...`.
The issue is repeatable both in my work and home networks. As far as I know, I've done no configuration changes or updates or such since the 10.8.3 update.
UPDATE: This may be hackintosh-related, since I get an error message from the bootloader saying
Unable to handle key preferred-networks. I'm not sure what this site's stance on hackintoshes is so I posted this on the bootloader's forum as well.
UPDATE 2: Not an issue of the bootloader.
Edit: In reference to Buscar's comment, this is my view of the network preferences: