It’s unfortunate that the Internet’s usfullness is compromised by websites such as this one. IGNORE the main piece of advice on this pag — that you should choose “wipe cache partition”. DO NOT. The Galaxy S4 phone has an entirely different, and obviously more appropriate option further down that same list you’re looking at. That option is, surprise, surprise: FACTORY RESET.
Quite why anyone would tell others that the best way to reset this phone is to choose “wipe cache partition” when, in fact, to perform a reset you need to click on the phone’s RESET option as it appears in the drop down menu, is beyond me.
If this is how I FIX IT goes about fixing stuff, Heaven help us all: utterly, blatantly, useless. I’ve wasted a lot of time scrupulously following the step by step advice on this page, even though my own commonsense kept shrieking at me that what I was reading about “wipe cache partition” was absolute nonsense. Don’t waste your time the way I have mine.