Android - How to reset Wi-Fi settings?

This has happened to me on several occasions, mostly when backing up/restoring Wifi settings using an app such as TitaniumBackup. Here's what I recommend, starting with the safest solutions:

1. First try going into the wifi settings and removing the problematic network. While you're there you might as well remove any other unused networks:
   https://support.google.com/android-one/answer/2819519 > Change, add, or remove saved networks > Remove

2. If that doesn't work, the only remaining option that doesn't require root access is to delete all of your saved networks.

3. If you don't want to delete all of your saved networks and you have root access, the wifi network settings are kept in a text file (/data/misc/wifi/wpa_supplicant.conf), which can become corrupted. I've been able to fix problems by manually editing the file:

   1. Turn off wifi (if you leave it on, the corrupted wifi settings may get rewritten)
   2. Back up /data/misc/wifi/wpa_supplicant.conf
   3. Edit /data/misc/wifi/wpa_supplicant.conf and remove any problematic networks.

4. If you've made it this far and you're still having problems, turn off your wifi and delete /data/misc/wifi/wpa_supplicant.conf. Of course this will delete all of your saved networks. The file will be recreated the next time you turn on your wifi.

5. As a last resort, you can delete /data/misc/wifi, but I don't recommend it. If you do decide to do this, make sure you back it up first. The folder should be recreated on reboot with default settings, then you'll need to set your networks up again.

I removed /data/etc/wifi, /data/misc/dhcp and /data/misc/wifi and it worked.