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Nsurlsessiond excessive CPU usage problem on Mac – details and workarounds

Although nsurlsessiond is a legitimate macOS process, it gets on numerous users’ nerves by chewing up a good deal of CPU, memory, and bandwidth.

What is nsurlsessiond Mac process?

An ideal operating system has yet to be invented. In the meantime, users may experience issues regardless of their software platform biases. These technical gotchas range from slowdowns and GUI unresponsiveness to app crashes and random reboots. Apple’s macOS is no exception. Over the past several years, it has undergone a fair dose of criticism over the misbehavior of a handful of daemons, including sysmond, trustd, syslogd, accountsd, and nsurlsessiond. The common denominator across all these user experience hardships is an abnormally high usage of CPU, RAM, and in some cases bandwidth. The last one on the list is increasingly breaking bad, as its consumption of computer resources suddenly becomes blown out of proportion. That’s not something people would expect from an important system process.

Mac process named nsurlsessiond may cause performance issues

To get the big picture, let’s see what nsurlsessiond is intended for. The “d” at the end means it is a daemon, that is to say, a background process that usually starts at boot time and performs predefined tasks to sustain a specific area of the system. Residing in the /usr/libexec/ directory, this one downloads and uploads content over a transport protocol such as HTTPS. Its specific role is to sync a user’s data with iCloud. With this in mind, it is normal to see it running behind the scenes whenever Apple’s cloud services are updating. The system performance footprint of nsurlsessiond remains inconspicuous as long as its CPU usage is under 10% or so. However, this number can get multiple times higher or even reach 100% and stay there. This will make the Mac slow down to a crawl.

Why does this spike occur when the resource consumption is supposed to be within a reasonable range? One of the main theories relates to a content storage glitch developed over time. Nsurlsessiond temporarily saves data to a directory inside the /var/folders/zz path. As these files accumulate, the interaction between the process and its allocated folder may become buggy. This randomly named location stores materials for years and starts exhibiting read or write access issues at some point. When nsurlsessiond tries to establish a data transfer session with the misbehaving directory, it fails. This repeats in a loop as the process keeps trying to reach the folder, which causes it to use more CPU, memory, and bandwidth than it should.

If this situation is the case, the user should sign out of iCloud, then sign back in and see if the problem persists. Another option is to deselect the Photos app and iCloud Drive in the service’s synchronization settings. In the event that the problem is still making itself felt after these operations, it is advised to stop the parent process named “trustd” via the Activity Monitor and then completely erase the obsolete subdirectory used by nsurlsessiond as the temporary storage for its data. This procedure is be described in detail further down.

One more scenario to consider is that this overuse of a Mac’s resources might stem from malware. Unwanted apps can tamper with the normal work of different macOS layers, including daemons such as nsurlsessiond. Some are tricky enough to inject rogue attributes into legitimate executables or pass themselves off as such processes so that the built-in system protection tools don’t detect them. This situation is far from being odds-on in the wild. However, it is definitely worth checking to determine further troubleshooting vectors. But first, let’s see how to eliminate the non-malware cause for misconduct of the nsurlsessiond process.

Stop nsurlsessiond from using too much CPU and bandwidth

This section covers an effective method to address the nsurlsessiond resource overconsumption problem that’s not caused by Mac malware. Since that’s the most common scenario, trying the following tips is absolutely worthwhile. In a nutshell, it will clean up unnecessary data related to this service that has accumulated over time.

  1. Open the Go menu, click Utilities, and select Activity Monitor. Find the executable named trustd, double-click it, and check its PID (process identifier).

    Determine the PID of trustd process

  2. Open Terminal from the Utilities list and type the following command: sudo kill -9 [PID of trustd], where the part in brackets is the number you determined in the previous step. Press the Enter key. This will terminate the parent process for nsurlsessiond.

    Terminate trustd process in Terminal

  3. Figure out the name of the system folder that stores old nsurlsessiond data. Enter the following command in Terminal and press Enter to do it: ls –la /var/folders/zz | grep nsurlsessiond.

    Run command to find out the nsurlsessiond temporary directory name

  4. The utility will return the pathname you need. Copy it to the clipboard.

    Name of the folder containing nsurlsessiond data

  5. Now remove this temporary system subdirectory by entering the following command in Terminal: sudo rm –fr /var/folders/zz [pathname determined in step 4]. Hit Enter.

    Delete folder with old nsurlsessiond data

  6. You may also want to delete system log files as an extra measure. Expand the Go menu, select Go to Folder, type /var/log/asl, and press Enter.

    Open system logs

  7. Select all items inside that directory and send them to the Trash.

    Clear the logs

  8. Restart your Mac.

Nsurlsessiond high CPU virus manual removal for Mac

The steps listed below will walk you through the removal of this malicious application. Be sure to follow the instructions in the specified order.

  1. Expand the Go menu in your Mac’s Finder bar and select Utilities as shown below.

    Go to Utilities

  2. Locate the Activity Monitor icon on the Utilities screen and double-click on it.

    Select the Activity Monitor

  3. In the Activity Monitor app, look for nsurlsessiond or another process that appears suspicious. To narrow down your search, focus on unfamiliar resource-intensive entries on the list. Keep in mind that its name isn’t necessarily related to the way the threat is manifesting itself, so you’ll need to trust your own judgement. If you pinpoint the culprit, select it and click on the Stop icon in the upper left-hand corner of the screen.

    Stop malicious process

  4. When a follow-up dialog pops up asking if you are sure you want to quit the troublemaking process, select the Force Quit option.

    Select the Force Quit option

  5. Click on the Go menu icon in the Finder again and select Go to Folder. You can as well use the Command-Shift-G keyboard shortcut.

    Use the Go to Folder feature

  6. Type /Library/LaunchAgents in the folder search dialog and click on the Go button.

    Open /Library/LaunchAgents folder

  7. Examine the contents of the LaunchAgents folder for dubious-looking items. Be advised that the names of files spawned by malware may give no clear clues that they are malicious, so you should look for recently added entities that appear to deviate from the norm.

    As an illustration, here are several examples of LaunchAgents related to mainstream Mac infections: com.updater.mcy.plist, com.avickUpd.plist, and com.msp.agent.plist. If you spot files that don’t belong on the list, go ahead and drag them to the Trash.

    Root-level LaunchAgents folder contents

  8. Use the Go to Folder lookup feature again to navigate to the folder named ~/Library/Application Support (note the tilde symbol prepended to the path).

    Open ~/Library/Application Support folder

  9. When the Application Support directory is opened, identify recently generated suspicious folders in it and send them to the Trash. A quick tip is to look for items whose names have nothing to do with Apple products or apps you knowingly installed. A few examples of known-malicious folder names are ProgressSite and IdeaShared.

    Application Support folder contents

  10. Enter ~/Library/LaunchAgents string (don’t forget to include the tilde character) in the Go to Folder search area.

    Open ~/Library/LaunchAgents directory

  11. The system will display LaunchAgents residing in the current user’s Home directory. Look for dodgy items related to rogue nsurlsessiond process (see logic highlighted in subsections above) and drag the suspects to the Trash.

    Contents of LaunchAgents folder in user’s home directory

  12. Type /Library/LaunchDaemons in the Go to Folder search field.

    Go to /Library/LaunchDaemons

  13. In the LaunchDaemons path, try to pinpoint the files the malware is using for persistence. Several examples of such items cropped by Mac infections are com.pplauncher.plist, com.startup.plist, and com.ExpertModuleSearchDaemon.plist. Delete the sketchy files immediately.

    LaunchDaemons folder contents

  14. Click on the Go menu icon in your Mac’s Finder and select Applications on the list.

    Go to Applications screen on Mac

  15. Find the entry for an app that clearly doesn’t belong there and move it to the Trash. If this action requires your admin password for confirmation, go ahead and enter it.

    Drag malicious app to the Trash

  16. Expand the Apple menu and select System Preferences.

    Select System Preferences

    Open System Preferences

  17. Proceed to Users & Groups and click on the Login Items tab.

    Proceed to Users & Groups

    The system will display the list of items launched when the computer is starting up. Locate the potentially unwanted app there and click on the “-” (minus) button.

    Delete unwanted login item

  18. Now select Profiles under System Preferences. Look for a malicious item in the left-hand sidebar. Several examples of configuration profiles created by Mac adware include TechSignalSearch, MainSearchPlatform, AdminPrefs, and Safari Settings. Select the offending entity and click on the minus sign at the bottom to eliminate it.

    Select Profiles under System Preferences

    Remove malicious configuration profile from Mac

    If your Mac has been infiltrated by adware, the infection will most likely continue to hold sway over your default web browser even after you remove the underlying application along with its components sprinkled around the system. Use the browser cleanup instructions below to address the remaining consequences of this attack.

To begin with, the web browser settings taken over by the nsurlsessiond malware should be restored to their default values. Although this will clear most of your customizations, web surfing history, and all temporary data stored by websites, the malicious interference should be terminated likewise. The overview of the steps for completing this procedure is as follows:

  1. Remove nsurlsessiond virus from Safari
    • Open the browser and go to Safari menu. Select Preferences in the drop-down list.

      Go to Preferences in Safari

    • Once the Preferences screen appears, click on the Advanced tab and enable the option saying “Show Develop menu in menu bar”.

      Advanced tab under Safari Preferences

    • Now that the Develop entry has been added to the Safari menu, expand it and click on Empty Caches.

      Empty Caches in Safari

    • Now select History in the Safari menu and click on Clear History in the drop-down list.

      Clear history in Safari

    • Safari will display a dialog asking you to specify the period of time this action will apply to. Select all history to ensure a maximum effect. Click on the Clear History button to confirm and exit.

      Select all history to clear

    • Go back to the Safari Preferences and hit the Privacy tab at the top. Find the option that says Manage Website Data and click on it.

      Manage Website Data option under Privacy tab

    • The browser will display a follow-up screen listing the websites that have stored data about your Internet activities. This dialog additionally includes a brief description of what the removal does: you may be logged out of some services and encounter other changes of website behavior after the procedure. If you’re okay with that, go ahead and click on the Remove All button.

      Confirmation dialog

    • Restart Safari
  2. Remove nsurlsessiond virus in Google Chrome
    • Open Chrome, click the Customize and control Google Chrome (⁝) icon in the top right-hand part of the window, and select Settings in the drop-down

      Chrome Settings

    • When on the Settings pane, select Advanced
    • Scroll down to the Reset settings section.

      Reset settings in Chrome on Mac

    • Confirm the Chrome reset on a dialog that will pop up. When the procedure is completed, relaunch the browser and check it for malware activity.

      Here’s how to reset settings in Chrome on Mac

  3. Get rid of nsurlsessiond malware in Mozilla Firefox
    • Open Firefox and go to Help – Troubleshooting Information (or type about:support in the URL bar and press Enter).

      Open Firefox and go to Help

      Select Troubleshooting Information

    • When on the Troubleshooting Information screen, click on the Refresh Firefox button.

      Refresh Firefox on Mac

    • Confirm the intended changes and restart Firefox.

Fix nsurlsessiond Mac process issues using Combo Cleaner removal tool

The Mac maintenance and security app called Combo Cleaner is a one-stop tool to detect and remove nsurlsessiond high CPU virus. This technique has substantial benefits over manual cleanup, because the utility gets hourly virus definition updates and can accurately spot even the newest Mac infections.

Furthermore, the automatic solution will find the core files of the malware deep down the system structure, which might otherwise be a challenge to locate. Here’s a walkthrough to sort out the nsurlsessiond high CPU issue using Combo Cleaner:

  1. Download Combo Cleaner installer. When done, double-click the combocleaner.dmg file and follow the prompts to install the tool onto your Mac.

    Download Combo Cleaner

    By downloading any applications recommended on this website you agree to our Terms and Conditions and Privacy Policy. The free scanner checks whether your Mac is infected. To get rid of malware, you need to purchase the Premium version of Combo Cleaner.

  2. Open the app from your Launchpad and let it run an update of the malware signature database to make sure it can identify the latest threats.
  3. Click the Start Combo Scan button to check your Mac for malicious activity as well as performance issues.

    Combo Cleaner Mac scan progress

  4. Examine the scan results. If the report says “No Threats”, then you are on the right track with the manual cleaning and can safely proceed to tidy up the web browser that may continue to act up due to the after-effects of the malware attack (see instructions above).

    Combo Cleaner scan report – no threats found

  5. In case Combo Cleaner has detected malicious code, click the Remove Selected Items button and have the utility remove nsurlsessiond high CPU threat along with any other viruses, PUPs (potentially unwanted programs), or junk files that don’t belong on your Mac.

    Combo Cleaner – threats found

  6. Once you have made doubly sure that the malicious app is uninstalled, the browser-level troubleshooting might still be on your to-do list. If your preferred browser is affected, resort to the previous section of this tutorial to revert to hassle-free web surfing.

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