Galaxy S5 won't remember wifi passwords

Check for software updates - just in case there are some pending

You can try wiping the dalvic cache - see http://www.pcnexus.net/2014/03/how-to-enter-recovery-mode-galaxy-s5.html

Just be sure to NOT "wipe data factory reset" - just wipe the dalvic cache and then reboot.

Unfortunately since the phone won't remember my wifi password, everytime it tries to update, it is interrupted because it is no longer on wifi. I have tried to update via Kies, but it says the phone is up to date. If that were true, why is the phone trying to update itself over wifi? This is beyond irritating. 

I also just wiped the cache. Entered wifi password, connected, restarted phone and wifi password was gone. I see I could possibly side load the update, but where would I find it in the first place?

I have a Galaxy S5 Active from AT&T, and I have a similar if not same issue. Whenever I toggle wifi off and back on, all wifi networks and passwords are forgotten. The same occurs if I restart the phone. I have not updated the security policy, so perhaps that is the issue.

This is somewhat frustrating given that I connect to many networks, and I occasionally like to turn off wifi to save battery while camping or spending the night at a friend's. Also, there are the inevitable lock ups or slow performance of the phone that require reboot. Please respond with any recommendations if you have knowledge about this.

Thank You

Michael

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Thank you jonna0812. Be careful with this fix. I was able to get it to work, but...

First let me say that I did root my phone, but be forewarned, this voids your factory warranty so proceed with caution. 

I deleted the supplicant file as the previous post said to do, but it did not recreate itself. So then I had no wifi at all. I finally found the stock ROM that worked and didn't take 12 hours to download. 

This was really pretty easy once I had the right files and there are tutorials on the web that explain how to do this.

Ultimately, my wifi password is saved after restarting my phone. It was quite a few hours of work to get there, but it is done! 

I had the same problem. I renamed the device under wi-fi settings, changed the clock to after 24 hours, tried it again, and it worked!!. You have to have enough space, and make sure, you rename the device. My device is at ver 5.5.1 now.