Hi, on Saturday my 4s (5.1.1) crashed after I tried to crop a screencap photo (screen went black with loading sign) then went back to home screen. Ever since then I've had loads of problems with the phone. Every now and then it will crash and restart (black screen and loading sign) by itself for no reason-- even when charging. The battery drains seriously quick to the point where I can't really take it off the charger and the device seems to get really hot. One time I left it on my bed and it was almost too hot to touch. I can't even check my emails anymore because the email app keeps crashing after a few seconds of loading.
I've tried reseting and rebooting. This morning I backed up the phone, made sure it was up to date, then did a restore with the latest iTunes. I didn't restore from backup as a new phone because I want to keep everything (media and content) from before. I mean I shouldn't have to because the phone should work anyway. And even after all that it still doesn't work. I've had this phone since last November so it seems strange that it's started doing this.
I don't live near an Apple store or Genius bar so I'm bringing the problem up on here and hopefully someone can help me? I've seen similar problems posted before but with no solutions so I'm quite pessimistic...
Ok so I'm making this post just in case anyone comes across this thread with a similar problem but, yes, I found a solution!
I downloaded the System Status app and it showed my CPU Usage was an alarming 100%. Even with all other apps closed, location services, iCloud and Siri turned off. Kind of strange right? So I looked at Diagnostics and Usage and it had nearly 100 reports that begin with "dataaccessd" and "MobileMail".
So I was going to turn off my mail accounts to see what that would do and as soon as I clicked the Hotmail address (under settings) it crashed. All other accounts (Gmail and 1&1) were fine. The problem was I couldn't deactivate the Hotmail account because it kept crashing so I did a full restore and started it as new phone instead of restoring a backup. Kind of gutted I didn't get to keep my girlfriend's text messages so F.U. Apple but it took about 1-1.5 hrs to put everything else back on again. I recommend an app called MyContentBackup Pro (about £1.49) to make a backup of all your contacts. The free version only lets you export the contacts via email (which doesn't work) so I had to go for the pro version.
Anyway that seems to have solved the problem but will report back if there's anything wrong. CPU Usage has been around the 3-30% mark which I think is normal. There is no overheating and the battery seems OK. For now. I'm guessing the problem was with the Hotmail account, making the Mail app crash, which kept sending diagnostic reports? Stuck in a loop? I haven't readded the Hotmail account to my mail just incase it brings up the problem again but, hey, at least I don't have to spend £30 going to the nearest Genius Bar or get a new phone.
Hope that helps,