Intermittent reboot

[Steve Swift]

My S4 occasionally reboots while it is in my pocket, powered on, and with plenty of battery charge. It just did it at 08:14 with 95% battery charge. I have the flip cover, so it's unlikely that some combinatiion of movements is causing the reboot.

In the past I installed an app which allowed me to suppress the power on sound, so I notice these re-boots because they do make the power-on sound. I think the app works by intercepting the shutdown process and muting the sound; it then re-establishes the original sound level following the next boot. So, whatever is causing the reboot, it seems not to be preceded by an orderly shutdown...

Is there any recording of reboot causes? How else could I determine what cases the reboots?

 

[dm3ready]

A quick solution MIGHT be to simply ensure that your battery is seated properly, especially if you have a non-OEM battery. Just a thought. Additionally, I think you might be onto something regarding the app you loaded. Did you try uninstalling the app to see if the problem corrects itself?

 

[beagle82]

My S4 occasionally reboots while it is in my pocket, powered on, and with plenty of battery charge. It just did it at 08:14 with 95% battery charge. I have the flip cover, so it's unlikely that some combinatiion of movements is causing the reboot.

In the past I installed an app which allowed me to suppress the power on sound, so I notice these re-boots because they do make the power-on sound. I think the app works by intercepting the shutdown process and muting the sound; it then re-establishes the original sound level following the next boot. So, whatever is causing the reboot, it seems not to be preceded by an orderly shutdown...

Is there any recording of reboot causes? How else could I determine what cases the reboots?

I would start by placing the battery on a flat surface and check for ANY bulging. If there is any bulging, then you may have found the issue.
If that is not the case, then you could restart the device in safe mode to determine if you have a bum app that is causing the problem.

 

[Steve Swift]

The app that I mentioned is "Startup Manager (Free)". I installed this in order to avoid the power-on "jingle", because I wake around 05:00 and turning my phone on was waking my wife as well...
As far as I know, the app is active only during the boot period, and during shutdown. I frequently don't turn my phone off for days, so Startup Manager is doing nothing when the reboots occur. I've had the app for a year or more, but the reboots are a new phenomenon. It's easy enough to disable it, or uninstall it though. I'll give that a go.

 

[Steve Swift]

I would start by placing the battery on a flat surface and check for ANY bulging. If there is any bulging, then you may have found the issue.
If that is not the case, then you could restart the device in safe mode to determine if you have a bum app that is causing the problem.

I placed the battery on a very flat surface. My battery's faces were so flat, the battery landed "softly" because of the tiny layer of trapped air between the mating suraces. Definitely no rocking.
The phone was bought new July 2013, and has the original battery. It lasts 24 hours or more, but I'm a light user of power-hungry features.
Perhaps there's a poor contact somewhere? If I'm lucky, removing the battery and re-inserting it may fix the problem. Fingers crossed...