What is nsurlsessiond and why is it using so much bandwidth?

2014-10-06 17:00

If you watch network traffic on your Mac, you may notice nsurlsessiond moving large amounts of data. Here is what it is.

What is nsurlsessiond?

nsurlsessiond is the daemon that handles background network transfers on behalf of apps using Apple's NSURLSession programming interface. When an app needs to download or upload data in the background, even after the app is closed, nsurlsessiond takes over and manages the transfer.

What uses it?

Many built-in and third-party features rely on nsurlsessiond:

iCloud Drive syncing files in the background
iCloud Photo Library uploading and downloading photos
App updates downloading from the Mac App Store
Any third-party app that uses background transfers

Why is it using so much data?

Common reasons for high bandwidth use:

iCloud Photo Library is uploading your photo collection for the first time
iCloud Drive is syncing a large number of files
A macOS or app update is downloading in the background
Desktop and Documents sync is on and you have many files

How can you cut its usage?

If nsurlsessiond is using too much bandwidth, find out what is syncing:

Check iCloud Drive sync status in Finder's sidebar
Check Photos, then Settings, then iCloud for upload progress
Check the Mac App Store for pending updates

You can turn off specific iCloud features in System Settings, then your name, then iCloud to cut background transfers.

Should you worry?

No. It is a real Apple system process. The data it moves belongs to your apps and iCloud services. If it seems stuck moving data without end, signing out of iCloud and back in usually fixes the problem.

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