LG G3 keeps restarting

So I bought a new phone.... suspicious thing is that as soon as I did, the problem on the LG STOPPED completely. While I can no longer make calls on the phone, pictures, internet at home, everything works just fine and no rebooting.  So.... it is not an issue with the actual phone but must be with something AT&T's service, not the LG phone itself.  Suggestions? I'm going to go back and talk to someone about it. My son's LG is starting to do the same thing.

Mine started right after my 2 years was up too!!!! Does @att or @LG do this through software so we have to replace them? Loved my LG G3 up to this point. Mine quit working at the worst possible time when my wife was emergency hospitalized for 3 weeks and I was long from home! Probably my last LG product!

This thread is interesting. ... My contract ends in February 2017, and like many people here I've been wondering if these issues aren't the result of planned obsolescence to force customers to buy a new device. It's a bit of a conspiracy theory, but in this day and age, that type of tactic would not surprise me.

My LG G3 started acting erractically about a week ago: Rebooting spontaneously; Wi-Fi failing to connect or not seeing the network; data function turning itself on even though I keep turning it off.

I've tried everything I could think of, even going as far as a factory reset, but the issue persists. An AT&T Online Tech Support specialist said my SIM card could be at fault. His diagnostic revealed it is one digit off from what it should be (4 instead of 3, whatever that means) and that it likely came from a wrong vendor. That is surprising, to say the least, since I bought the phone from AT&T almost two years ago.

The tech specialist suggested I go to an AT&T Corporate store to get a free replacement. He emphasized "corporate store," because a retail location would charge for the the SIM card.

While researching this issue, I've also come across several threads that suggest a faulty battery may be at fault. A new battery is not too expensive, so it's worth a try.

Quick update: I got a new SIM card from an ATT corporate store, but that didn't fix the issue. I did order a battery replacement from the LG online store for $15. Although cheaper alternatives existed on Amazon and elsewhere, I could never verify whether the battery was genuine or a knock-off. As of this writing, I haven't received the battery yet. I'll update with results (or lack thereof) when I do.

I had the same problem -- my LG G3 was continuously re-starting. 

The problem stopped when I replaced the battery.

One way of diagnosing the problem would be to see if it happens only when you are using the battery. This is what happened to me.

Here's another idea: If you are waiting for the replacement battery to arrive, as a temporary solution, you could keep the cell phone plugged into one of those small portable external batteries.

Before replacing the battery, I tried uninstalling apps, and even reset the phone to factory state, but that did not solve the problem. Only replacing the battery made a difference.

Spoke to LG, they said it needs to be mailed in and the motherboard worked on.  The person that I spoke to said after that happens then he has not heard of anybody calling back with a complaint.   So there is something on the motherboard that needs to be fixed.

exactly whats happening with mine. itll keep flashing the LG screen and then if i throw it on the charger , booom it works. have you figure out the problem ? if so please let me know. thank you!