[Galaxy S6 Active] Antosino:
I'm having a somewhat similar issue. My S6 Galaxy Active is just randomly shutting down. Say I call somebody and they don't answer; I set my phone down after hitting the power button to lock the screen. Twenty minutes later I go to check it, and it's just off. I have to turn it back on and now don't know if I received a call or not (unless a voicemail was left) and it's very annoying.

This started out rare and has now become more frequent. At first it wasn't too often and generally only happened when the phone was "resting" on a desk or my bed with the screen off. In my last call with my girlfriend it shut down THREE TIMES during our conversation.

Now, during the conversation the phone was against my head so the screen was still off. I haven't ever noticed it happening with the screen on. This has started to happen within minutes of a prior shutdown, like 40 times a day, and it's insane. While I'm not 100% sure I'm about 90% that it only happens while the screen is off. It's not restarting, it shuts down completely and remains that way until I power it on again. It's not buttons being pushed accidentally as it will be set down entirely by itself and still shut down.

Another, possibly related, problem is that sometimes the screen is blank. I'll turn the phone back on and will hear the startup sounds, but there is just no picture. The screen is dead. I will have to force-shutdown the phone (volume down + power) to fix this. Sometimes it restarts with no screen again and I have to do this several times, but it always is fixed eventually. This happens much less frequently than the shutdown problem but is still an annoyance. I've also noticed some... flickering, while the phone is in use. This is even more rare but has also started to happen a bit more. I'm not quite sure how to explain it... a portion of the screen may compress, or "wrap" around. For instance, the bottom portion of the screen (let's say the bottom 1/8th of it, if you divided it with horizontal slices) will "wrap" and be shown at the top, distorted with random discolorations (generally purples, greens) along with sometimes being twisted at an angle. This usually happens for a few seconds and goes away.

My main concern is that I've taken great care of this phone. It has never been dropped outside of slight falls from pocket/hand level onto carpet. It's never been submerged or even gotten wet at all. On top of all that, it's an ACTIVE! It shouldn't really matter if it DID get wet; regardless, although it's an Active it's been cared for as if it weren't. This simply cannot be a result of physical neglect unless somebody is sneaking into my house at night to chuck my phone at a wall. The phone is... I'd say a year and a half old? I bought it when the S6 was still the newest Galaxy, I believe AT&T had somewhat recently obtained the rights to sell it. I'm sure I could find the exact date of purchase if it mattered.

I didn't want to make an entirely new thread for this, but I'm sorry if I've hijacked this one. If I should make my own thread instead I will, I just figured keeping the main boards clear of clutter was a better choice.

Thank you to anybody that can help. I'm guessing my only options are "replace it" or "take it in" but I'm hoping there's a solution. I know I can wipe the cache, factory reset, etc. I will add that I am very, very full in terms of memory; I might have around 500gb free. I'm not even sure what's really taking up all the space as all my music is in the Cloud, I'd have to check, I guess Apps? The Active not having an SD slot really sucks. I don't think low free space could result in shutdowns, I work in the IT industry and can't think of a reason why it would... unless something absurd is happening, like the phone is running out of RAM, trying to use SWAP, there's not enough space (although it would be pre-allocated and this wouldn't happen, no?) and so it shuts down? I don't know.

I'm thinking it might be as simple as a loose battery connection, as so far my tests seem to show that this DOES NOT HAPPEN while the phone is plugged in, so it seems like some sort of quick power failure? Unfortunately I am unable to check the internals myself as I do not want to void any potential warranty; I think I may have purchased the replacement plan and will be checking tomorrow. If I'm going to void my warranty it's going to be with a root, not exploratory surgery (at least not until I'm 100% sure what to look for). Anyways, thanks for any help.