Hi there. I've been having this issue for as long as I can remember. My phone often (many times a day) will turn off during use, requiring me to remove the battery and re-insert the battery to get it turned on again. I can't determine why it's happening, though certain apps tend to force it to happen more regularly than others. For instance, using the base camera app almost always results in the phone turning itself off after I've taken a standard photo (often it turns off while focusing, let alone if I dare be so cheeky as to try and use something like the selective focus mode). Other apps, as I've mentioned, cause the same thing more often than others (graphic/colour-heavy app screens, for example) - but it will regularly happen during the use of any app. There's no correlation between specific apps and the phone deciding to turn itself off. That's not the end of it, however. If I happen to open my phone's cover (I use a Samsung leather case with a swinging door - for want of a better description - which opens and closes) within two or three minutes of having re-inserted the battery the screen will turn on for half a second and then it will go to black again. Cue battery removal, phone turn-on and a several-minute wait to use the phone again. Often it'll only be a few minutes until I'm required to go over the whole lot again. I thought it may have been the battery - the one that came with the phone would often jump from 40% battery in reserve to 0% in one jump when I opened Snapchat, shortly before it turned itself off and required a charge from 0%. I've since replaced the battery with an aftermarket one - the 40%-to-0% has stopped, but the issue I've described in the first paragraphs persists. I should note I got so sick of the battery dying instantly that I deleted Snapchat (it was un-usable in that condition) and haven't installed it back for several months. Perhaps if I had the app still this issue would have returned, I can only guess. Strangely enough, the sudden turn-offs didn't occur using the old battery. I've sort of replaced one issue with another in my attempt to resolve the problem. But the old one is clearly faulty - I tried it recently to see if it was usable and it would go flat at around 50% battery level. A friend suggested it may have been the case causing the issue (especially as the phone turned itself off when I opened the cover on start-up, and the cover has connections to the back of the phone) but today I took the cover off and operated the phone cover-less to see if it would fix the issue. No luck. Turned itself off in classic fashion, after only 30 seconds of use. The phone model number is SM-N915G and the software version is 6.0.1. I updated the software yesterday or the day before, hoping that it might resolve the issue. If anything it seems to be worse now. It might be important to mention that I've not had any issues with turning off while the phone's been plugged into a power source. Not that it doesn't necessarily happened, but I've never experienced it while it's been on charge and I've been using it - if it occurred at the same frequency as it does when not plugged in I'd have surely experienced it at least once before. I bought the phone on a plan early last year, so it'd be out of warranty by now I assume. Really I should've taken it in a year ago when the issues were around then, but there's not a whole lot that sort of thinking can do to help me now. I apologise if my first post is a bit long-winded, I hope it's given a pretty clear idea of my issue. I've been a loyal Samsung phone user for years now and this experience has really dampened my feeling toward the quality of their products; it's just been such a frustrating experience. I hope any of you can help me out, I'd be ever so appreciative of any help. Many thanks.