Drippy

Why is my Mac using so much data?

When a Mac eats gigabytes you didn't use, it's almost always one of the same few background jobs. Here's the list, and how to tell which one it is.

Updated November 2026

Download for macOSPricing

The usual suspects

  • macOS updates (softwareupdated): a single update can be 5–15 GB.
  • App Store and app updates (nsurlsessiond, appstoreagent).
  • iCloud Photos (cloudd, photolibraryd): uploads new photos and downloads originals.
  • iCloud Drive (bird, cloudd): syncing big folders like Desktop and Documents.
  • Third-party sync: Dropbox, Google Drive, OneDrive.
  • Online backups: Backblaze, Arq, CrashPlan uploading continuously.
  • Browser tabs that autoplay video, or streaming left running.
  • Game launchers: Steam and others patch in the background.

Find which one it is

Live, from Terminal:

nettop -P -d

Activity Monitor's Network tab works too, but it loses an app's numbers as soon as the app or the Mac restarts. Drippy keeps them by day, so you can see what used the data yesterday.

Stop it

  1. Automatic updatesSystem Settings › General › Software Update › ⓘ next to Automatic Updates. Turn off downloads.
  2. iCloud PhotosPhotos › Settings › iCloud, or Pause in the Library view.
  3. Sync and backup appsPause them from their menu bar icons while you're on a capped connection.
  4. Low Data ModeSystem Settings › Wi-Fi › Details… for the network. Apps that support it hold off on background work.

Questions

Why is my Mac using data when I'm not using it?

Background updates, iCloud sync and backup apps run when the Mac is idle. nettop or Drippy show which one.

How do I stop my Mac from downloading updates?

Turn off automatic downloads under System Settings › General › Software Update › Automatic Updates.

What is cloudd and why is it using so much data?

cloudd is the macOS process that syncs iCloud data, including Photos and iCloud Drive.

Download Drippy

Download for macOS