macOS can be surprisingly chatty in the background, even when you're not actively doing anything. From what you’re describing, it sounds like something is aggressively pulling background data, and we’ll need to take a layered approach to isolate and stop it.
First, let’s look at `nsurlsessiond`. This process handles background network sessions, often related to iCloud services (Photos, Drive, etc.), App Store activity, and third-party apps using background fetch.
To reduce them:
- Open System Settings > Apple ID > iCloud, and disable syncing for Photos, iCloud Drive, and iCloud Private Relay (temporarily).
- Also, check Mail under iCloud and set it to “Manual” or fetch less frequently if it’s active.
- Quit all open apps and wait a few minutes. Open Activity Monitor, go to the Network tab, and sort by Sent Bytes or Received Bytes to identify culprits.
Next, go into System Settings > Network > Wi-Fi > Details for your current network and uncheck “Private Wi-Fi Address” and “Limit IP address tracking.” These features can cause more background chatter in certain environments. Also, if you're using Safari, go into Settings > Safari > Search, and disable:
- Safari Suggestions
- Preload Top Hit
- Search engine suggestions
If you're not using Safari, try disabling similar features.
Lastly, you might want to create a new network location under System Settings > Network, which gives you a clean slate without previously cached DNS or proxy configurations.
