I’m using iOS 13.2 on an iPhone X, and would like to drastically reduce the amount of cellular data my phone is using. In less than a month, my phone has used 10.7 GB of cellular data. 8.5 GB of that is from “System Services,” with 7.9 GB coming from “Documents & Sync.”

Is there any way to see what is using all of that data, or to control what happens over cellular vs waiting for Wi-Fi? My battery also dies quickly, and assume that is related to how much cellular data is being used in background.

What I tried:

  • I turned off iCloud Drive syncing over cellular network yesterday morning and then reset cellular data usage statistics. Since then, Documents & Sync has used used 1.0 GB of cellular data .

  • I’ve had “Low Data Mode” turned on under Cellular Data Options for the entire month, which doesn’t seem to be helping at all.

  • I tried erasing all content and settings and restoring from backup. This may have helped slightly, but it still seems to be using large amounts of cellular data

  • In the two days since I asked this question, "Documents & Sync" has used another 500MB. I was mostly at home over the weekend (on WiFi), and when I was away from home I wasn't doing much on my phone (and nothing that would use large amounts of data ) Nov 4, 2019 at 16:26
  • 1
    At the end of the cellular statistics (after they load) do you have iCloud Drive turned on ? Try after turning it off. Also, since photos, notes, iTunes etc separately have their usage, I seem to see only iCloud Documents or back up to be the thing. Also turn off backup in iCloud preferences.
    – anki
    Nov 9, 2019 at 23:13
  • I turned off the iCloud Drive over cellular setting — thanks for flagging, I didn’t know about that setting there. I just reset my statistics — it would be nice to have more granular controls, but some control is better than nothing Nov 10, 2019 at 15:43
  • Strangely, that seems to not have had any impact. I turned off iCloud Drive syncing over cellular network yesterday morning and then reset cellular data usage statistics. Since then, Documents & Sync has used used 1.0 GB of cellular data Nov 12, 2019 at 1:19
  • 2
    @Najinsky I had iOS 13 installed for over a month — it would be strange to sync that much data over cellular alone for over a month after install (in addition to everything syncing over Wi-Fi, which I am connected to 90% of the time). Definitely could be a bug, but given the amount of data for that long, it doesn't seem intentional Nov 18, 2019 at 17:38

4 Answers 4


Take a look at "Wi-Fi Assist", which is found at Settings --> Cellular --> right near the bottom of the list. This setting uses your cellular data when Wi-Fi connectivity is poor.

This may account for cell usage even when you have iCloud Drive turned off.

  • 1
    It's not that. It shows its own usage broken out and is a very small amount (2.6MB over the past week for Wi-Fi assist vs 808 MB for Documents & Sync) Nov 20, 2019 at 16:08
  • Same here, WiFi Assist was turned off and data was still leaking away.
    – kalmiya
    Jan 21, 2020 at 17:48

Running into this exact same problem, disabled every single option vaguely related to "data" and "iCloud" in the settings, and in my specific case tracked it down to WhatsApp leaching huge amounts of mobile-data (each time 1-2 megabytes within 1-2 minutes - and increasing - after disabling WiFi and enabling 4G).

If you run into this problem and have WhatsApp installed, try the following: Open the settings, click on your name/cloud-account at the top, select iCloud and in the list with apps disable WhatsApp (at the very bottom).

Note: There might of course be more reasons or other apps causing "documents & sync" leeching data. Interesting is that even if an App is disallowed access to mobile data, via writing to iCloud it can apparently indirectly cause usage of mobile data.

  • For me, it also was an app that caused this, consuming about 60 MB per day with Documents & Sync - I left iCloud syncing on, then switched off all possible switches from the settings in the iCloud section, and the problem was gone. Then I switched them on one by one over a few days and observed the mobile data usage, which lead to a small game that apparently uses iCloud for whatever and uses 60 MB a day on syncing via mobile network - so switching everything else on and that app off in the iCloud settings did the trick.
    – TheEye
    Oct 28, 2020 at 10:30
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    I really wish Apple would split up which apps are exactly using how many mobile data in Documents & Sync ... would make tracking much easier
    – TheEye
    Oct 28, 2020 at 10:32
  • In my case it was WhatsApp too. Eating 2gb of mobile data in 24hrs! Disabling iCloud for WhatsApp helped
    – jitbit
    Jan 30, 2022 at 21:19

I have the exact same issue. It started on Nov 9th and has continued since then pretty consistently. I had cellular data turned off for iCloud Drive, and I have background app refresh set to WiFi only. Also no iCloud photos turned on. I use Photo stream but have also set it to wifi only. I thought I'd started to troubleshoot the issue yesterday. I turned off my MacBook Pro (using the same iCloud account) before I left for work in the morning, and the documents and sync number didn't go up much all day. But today, I turned off its wifi before I left for work and it went up by about 400mb.

This is very frustrating not to be able to see what 'document is syncing' just a black box that's using insane amounts of data and forcing me to turn off cellular data unless I need it. Any troubleshooting suggestions welcome!


Figured out my issue. Was an iCloud shared video (sent to me via iMessage) that was on my phone but somehow was still constantly syncing.

Maybe check there?

  • How did you find out that it was syncing? Dec 5, 2019 at 17:03
  • I noticed that my documents and sync was rising around 2-5mb per minute. So I was shutting stuff off, basically just testing things until I had it narrowed down. Then I remembered that my girlfriend had sent me a video of our cat (that came through iCloud sharing as it was too big to come via iMessage) around the same time as all of this started. So I checked in the photos app and the video was still there but when I tried to play it, the photos app quit. I reopened it and tried to play it again. Worked the second time. So I figured something was up. I deleted the video and problem solved. Dec 6, 2019 at 19:32

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