coretime.ips

That's a diagnostic message for Apple to analyze (if you have that option enabled). There is no useful information in it that you can use.

I don't believe you can control whether the information is logged or not. It is there for all IOS 8.2 users I believe. All you can control is whether the information gets sent to Apple or not.

I have no idea what's causing it but it is annoying and the logs are quite long. One each day around midnight.

How do you keep it from sending!? I think it's responsible for much of my data 'drain' so how do you prevent it from going out/using your cellular data?

It is not responsible for your battery drain. It is just text. The phone would have to send hundreds of them to even approach the data required to send one picture message. But if you want to stop sending anyway go to Settings/Privacy - Diagnostics & Usage. Tap Do Not Send.

As a followup, you don't have to guess what is using your data. You can go to Settings/General/Usage and tap on Manage Storage under the Storage category.

Hi, thanks for responding! I've been on the phone with Apple store, Apple Support, At&T and Googling all for a few hours in the past few weeks. The skyrocketing usage of my data allotment just started in the last few weeks. IT APPEARS to have started after my daughter tried to put a few songs on for me which she'd done before. Either by prompt or accident she deleted all the info off my phone. A recent backup helped me replace the info but my problem started soon after. My manual usage had always been fairly consistent previously. I haven't changed my usage time or pattern.

To fix I've downloaded most recent (8.3), cut off 'cloud drive', have no added apps, nothing is on in cellular data. I can only keep much data from being used by keeping safari closed, just use it on wifi. If I turn it on for even a minute, a lot of data gets sent somewhere (maybe pent-up or saved from earlier gathering?). I've had the 'don't send' button you mentioned checked for some time (although it may have been 'on' when I first started having problems). I only leave cellular data in general on because I understand it has to be to receive/send texts (virtually all i-messages). Doing all this, I keep my data usage very small right now--but, imagine, I'd like to use my phone! like I used to--every few days maybe looking up something on Amazon, Ebay or Google info for only a few minutes each time at most. I often used it just within wifi.

In that storage I'm showing photos and camera as biggest user although I only have 79 pics, 1 short dog video clip and 26 deleted pics (I just did a final delete of them, apparently deleted they were still on there).

To clarify, it's not the data stored that's costing me in usage but the data being sent somewhere without my instigation or consent (that I know of). Like at night when I'm in bed 20,000-40,000 KB were being sent somewhere before I instituted all these controls. So CoreTime is not sending with that 'don't send' checked and it's not gathering much data anyway, right?