[KFINPGH]

I have a refurb GS4 from ATT. I put an Otterbox Defender on it, but I doubt that is causing these problems:

Phone randomly disconnects from ATT Mobile and 4G, but keeps wi-fi going. I don't realize that I am not connected unless I try to use dual authentication and get no SMS message or am told that someone tried to call me, but the phone didn't ring..

Phone also shuts off alarm and notifications until it's restarted. It's a good thing I have a back up alarm or I would have overslept many times.

A restart fixes the problem, but only temporarily. I have removed WAZE and Clean Master apps.

I use a battery monitoring app and can see when the phone is in "hyper drain" mode. It's warm to the touch and I lose 30% battery life in 15-20 minutes. That problem goes away when I reset.

I don't want to reset the phone multiple times a day; it makes me wonder if Android 4.4.2 and the GS4 are reliable.

ATT hardware center did a battery pull, but that is a pain when the device is in an Otterbox case.

Anyone have any ideas or suggestions? Thanks.

[B. Diddy]

Welcome to Android Central! Have you tried a cache partition wipe? It won't erase any personal data: Reset: Samsung Galaxy S 4 | T-Mobile Support

Also, consider unmounting your SD card (in Settings>Storage), removing it, and rebooting. A corrupt card can cause various problems.

[KFINPGH]

Thank you for your quick reply.

I did the cache wipe and we will see what happens. How often should that be done?

I assume the only cure for a corrupt SD card is to back up all of the data and format the card using the phone's OS. Does the format utility offer both a quick and extended format similar to DOS? It's a 32 GB card, but I have used maybe 3 GB. The camera stores pictures on the SD card and I copied older pictures to the card using a USB cable and Windows. I may be better off using Google drive and downloading the older pictures to the phone using that app if I want to view them while offline or where there is no data service.

[B. Diddy]

There's no real recommendation for how often to do a cache partition wipe. I would suggest doing it if you notice issues with performance or odd glitches.

Formatting SD cards is always a bit of headscratcher for me. In my experience, most phones need the SD card formatted in FAT32 (although I think some phones will read NTFS or exFAT), and I don't believe Windows 7 or 8 has the native ability to format an SD card into FAT32 any more. Phones will usually ask you if you want to format an unformatted card, but I'm not sure if they have an option to do so if the card is already formatted. Hopefully someone else can weigh in here.