What Is nsurlsessiond and Why Is It Using My Wi-Fi?

If your internet suddenly feels incredibly slow, or you get an alert from your internet provider that you are nearing your data cap, your Mac might be downloading something massive in the background.

When you open Activity Monitor and check the Network tab, you will often find a cryptic process named nsurlsessiond sitting at the top of the list, quietly pulling down gigabytes of data.

What is nsurlsessiond, and how do you make it stop? Here is a simple explanation of what this process does.

The Background Downloader

nsurlsessiond stands for NSURLSession Daemon.

It is an official Apple service built into macOS. Its only job is to handle background downloads and uploads for other applications.

When an app needs to download a large file, but it knows you might close the app before the download finishes, it hands the task over to nsurlsessiond. The nsurlsessiond process will continue downloading the file in the background, even if the original app is completely closed.

Because it handles tasks for so many different apps, it is totally normal to see nsurlsessiond using network bandwidth.

What is nsurlsessiond Actually Downloading?

Since nsurlsessiond is just a delivery service, high network usage means some other app asked it to download a massive file. The most common culprits include:

1. iCloud Drive Syncing

If you just saved a huge folder of videos to your Desktop, and you have iCloud Drive enabled, macOS will use nsurlsessiond to quietly upload all those videos to the cloud in the background.

2. Photos App iCloud Sync

If you took hundreds of 4K videos on your iPhone over the weekend, your Mac will use nsurlsessiond to download all of those high-resolution files from iCloud into your local Photos app.

3. macOS Software Updates

Apple uses nsurlsessiond to pre-download large macOS system updates. It downloads the 5GB update package in the background so that when you eventually click "Update Now," the files are already waiting on your hard drive.

How to Stop nsurlsessiond High Bandwidth Usage

If nsurlsessiond is completely choking your Wi-Fi network, you have a few options to reign it in.

• Force quit the process: You can select nsurlsessiond in Activity Monitor and force quit it. macOS will eventually restart it, but this instantly pauses whatever massive download was happening, giving your network a temporary break.
• Pause iCloud syncing: Open the Finder, look in the sidebar under iCloud Drive, and see if there is a pie chart icon indicating a sync in progress. Click it to pause the sync.
• Turn off automatic updates: Go to System Settings > General > Software Update, click the "i" icon next to Automatic Updates, and uncheck "Download new updates when available".

Keep an Eye on Background Downloads

Activity Monitor is great for showing you that a download is happening, but it buries that information in complex tabs and data tables.

If you want to know the second an app starts hoarding your bandwidth, you should use MacStats.

MacStats is a native menu bar app that tracks your network upload and download speeds in real time. You do not have to open a separate app to see if your internet is being used.

If you notice a huge spike in network traffic, click the active process in MacStats and use the AI Process Explainer. It will instantly translate a confusing name like nsurlsessiond into a plain English explanation, telling you exactly what the process does.

Stop wondering where your internet bandwidth went. Download MacStats for Free and monitor your network speeds in real time.