I searched the web and apparently this process has something to do with the iCloud Drive! I don't have more than 10 MB for all the data and documents on iCloud Drive; but this process uses more than 300 MBs everytime it starts. It usually starts within a restart of the computer. I also checked the setting of iCloud drive on my iPhone and disabled all data backups and stuff for applications (even whatsapp and others which are not even on my mac). I have no idea what's causing this bandwidth hug. All photos cloud stuff has been turned off too. I don't use safari either; using chrome.

So what exactly is going on? Is the only way to fix this, turning off the whole iCloud Drive thing? Is this a bug? I'm using Yosemite 10.10

I like using iCloud drive to sync all Pages and Numbers documents between my iPhone and Mac (Which together are not more than 10 MBs).

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  • To clarify. Are you monitoring nsurlsessiond on OS X or is the problem on iOS? It would be best to focus on one platform at a time / ask two questions so the answers could focus on appropriate tools for different platforms.
    – bmike
    Sep 4 '15 at 14:06
  • @bmike I'm monitoring nsurlsessiond on OS X. I added the iOS details to demonstrate that no extra data is coming from iOS.
    – Milad
    Sep 4 '15 at 18:39
  • Anyluck ? I have lots of b/w being eaten by nsurlsessiond I even signed out of iCloud but still something is downloaded in background.
    – GoodSp33d
    Sep 6 '15 at 8:39
  • @GoodSp33d nothing yet! :( It's probably a bug.
    – Milad
    Sep 7 '15 at 6:41
  • @MiladGhattavi I am not using any of the cloud utilities, and was able to get these tasks stopped by running these scripts. But I guess in your case you want sync for few of the utilities.
    – GoodSp33d
    Sep 7 '15 at 8:35

The NSURLSession Daemon (nsurlsessiond) is used for uploading and downloading content. Apps can delegate transfers to the daemon which continues the transfer even after the delegating app quits.

So it could be any application. It's not restricted to Apple apps and services, all apps can use this daemon.


Have you got photos in iCloud already? If so it could be the Photos app on your Mac downloading from iCloud.

I have had particular issues with this process using huge amounts of data when the storage on your Mac is low and you have "Optimise Mac Storage" enabled. Because it can't store all of the photos locally, it downloads them from iCloud and can sometimes become stuck. This quickly uses masses of data.

Try pausing syncing for one day to see if that helps.

To do this: Open Photos > Preferences > iCloud > Pause for one day.

If that helps you might consider disabling the iCloud features of Photos entirely in that same menu.

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