No. nsurlsessiond does background transfers on behalf of other apps.
It runs as _nsurlsessiond from /usr/libexec/nsurlsessiond.
Because apps hand their background transfers to nsurlsessiond, Activity Monitor shows the data under its name instead of the app that asked for it. If it's using lots of bandwidth, check iCloud Photos and Drive sync status, pending software updates, and podcast downloads. Pausing iCloud sync (in Photos or Finder) usually calms it down.
Facts
- Owner
- Apple (part of macOS)
- Network-related
- Yes
- Typical ports
- 443
- Block it?
- Don’t block it
What it connects to
| Host | Country | Purpose |
|---|---|---|
| Apple servers (iCloud, updates) | Various | iCloud sync, App Store and system downloads |
| Third-party app servers | Various | Background transfers apps hand to the system |
Should you worry?
No. nsurlsessiond does background transfers on behalf of other apps. When it uses a lot of data, something is syncing or downloading: usually iCloud Photos, iCloud Drive, or an update.
Frequently asked questions
Why is nsurlsessiond using so much data?
Something is syncing or downloading in the background: iCloud Photos or Drive, software updates, App Store downloads or podcasts. It's doing the transfer for another app.
Can I stop nsurlsessiond?
Not permanently; macOS restarts it. Pause the sync or download that's causing the traffic instead.
Is nsurlsessiond a virus?
No. It's a signed Apple system daemon in /usr/libexec.