Nslookup.exe keeps popping up, uses high CPU, is it virus?

Published by Nyau Wai Hoe - Updated on

While navigating your day-to-day computer tasks on Windows 11 or 10, you might encounter a situation where a process labeled as nslookup.exe keeps popping up, causing an unusually high CPU and memory usage. This can understandably cause some concern, especially if your system begins to slow down or behave erratically. This comprehensive article will look into the nature of nslookup.exe (typically located in the System32 folder in Windows), its purpose, reasons for causing high resource usage, and address a commonly raised question: Is nslookup.exe a virus?

Also see: How to Scan an .exe File for Viruses to Check If It’s Safe

Nslookup.exe keeps popping up

What is System32 nslookup.exe?

Nslookup.exe is a genuine executable file that is integral to the Microsoft Windows Operating System. The term nslookup is an abbreviation for “name server lookup.” This utility is designed to query the Domain Name System (DNS) to obtain domain name or IP address mappings, or other specific DNS records. DNS is a crucial Internet service that works like a phonebook for the Internet, translating human-readable domain names into machine-friendly IP addresses. This translation is necessary for systems to establish connections over the network, enabling you to visit websites, send emails, and more.

The nslookup.exe file is typically located within the System32 directory, a vital part of the Windows OS. The System32 directory contains system files and software libraries needed for the proper functioning of the Windows operating system, including the nslookup.exe.

What is System32 nslookup.exe

By running an nslookup.exe command in the command prompt, you can find out which IP address corresponds to a specific domain name, and vice versa. For instance, running the command nslookup facebook.com will return the IP address(es) associated with this domain. This capability is essential for network administrators to troubleshoot DNS servers and to verify that they are working correctly.

Useful tip: How to Know If an App is Using The Internet in Windows 11

Why is nslookup.exe causing high CPU and memory usage?

Usually, nslookup.exe should not cause any noticeable CPU or memory usage as it’s a lightweight utility designed to perform discrete network operations. However, if you notice high CPU or memory usage, there might be a few reasons for this.

nslookup.exe high CPU and Memory usage

  1. Network Issues: The system might be continuously performing DNS lookups due to a problem in network configurations or an unstable internet connection. This continuous operation could lead to a spike in CPU or memory usage because the system is perpetually trying to resolve these issues.
  2. Malicious Programs: It’s also possible that a malicious program or virus is exploiting the nslookup utility, triggering it to behave abnormally and use more resources than it typically would.

Recommended guide: How to Limit CPU Usage of a Process in Windows 11

Is nslookup.exe a virus or malware?

The legitimate nslookup.exe is not a virus. It’s an essential tool provided by Microsoft for network-related tasks. However, it’s crucial to understand that malware authors often give their malicious files names that closely resemble those of legitimate files. This tactic aims to evade detection by both users and anti-virus software, making it more challenging to identify and eliminate the threat.

Therefore, if you’re experiencing high CPU or memory usage related to nslookup.exe, there’s a chance that your system may be infected by a virus.

How can you verify if it’s a virus?

You can follow these steps to confirm if the nslookup.exe file is legitimate or malicious:

  1. Check the File Location: The genuine nslookup.exe is usually located in the C:\Windows\System32 directory. To check this, right-click on the process in the Task Manager and select “Open file location”. If the revealed file location is different, it could be a red flag.Check if nslookup.exe is a virus or malware
  2. Scan for Viruses: Use a trusted anti-virus software to scan the exe file to check if it’s safe. Click on “Scan for viruses” after you’ve opened the file location. This action can help detect any potential threats.Scan exe file using antivirus software

How to address high CPU and memory usage by nslookup.exe?

If you’ve noticed that nslookup.exe is causing high CPU and Memory usage on your Windows PC, here are some steps that you can undertake to address the issue:

  1. Restart your computer: A simple restart often solves many problems. It can clear out any temporary files or processes that might be causing issues.Restart Windows 11
  2. Check your network: Ensure your network settings are correct, and your internet connection is stable. Improper DNS settings could lead to continuous DNS queries, causing high CPU usage. You may need to contact your Internet Service Provider (ISP) for help.
  3. Scan your system for malware: If the location of the nslookup.exe file is not C:\Windows\System32, or if your antivirus software flags it as a threat, scan your entire system for malware.Run a full virus scan on Windows 11

Related concern: Why is My Memory Usage So High When Nothing is Running?

Insights from Reddit users about nslookup.exe

Reddit users can often provide valuable insights and discussion points on a variety of topics, including those related to system processes like nslookup.exe. According to one user, the continuous popping up of the nslookup.exe process could be due to another process initiating an nslookup command or a scheduled task within Windows Task Scheduler triggering this event.

Nslookup.exe Reddit

The nslookup utility in itself is harmless. As a native Windows tool, its main function is to query the IP address or the name of a domain from the DNS server. Running nslookup commands like “nslookup google.com” in the command prompt should present the IP address for Google.com as per your DNS server information.

nslookup command in Windows 11

It was also noted that while it’s doubtful for a virus to disguise itself as nslookup.exe, the possibility cannot be entirely ruled out.

To deal with a recurring nslookup.exe issue, the following areas can be checked:

  1. Task Scheduler: This tool allows you to manage the tasks that are scheduled to run at specific times. To find the task that’s causing the issue, type “task scheduler” in the start menu. You can then analyze what commands the task is running and when.Task Scheduler Windows 11
  2. Startup Programs: You can review your startup programs in the Task Manager Startup tab or use Microsoft Sysinternals Autoruns. These tools show you the programs that start upon system boot.Disable Startup Programs in Windows 11

Can I remove nslookup.exe?

Nslookup.exe is a system process and an integral part of the Windows operating system. Therefore, you should not attempt to remove it. The utility is essential for network troubleshooting and performs crucial DNS lookups that enable your computer to communicate over the internet.

Can I remove or delete nslookup.exe

However, if you suspect that a file named “nslookup.exe” is causing issues and it is located outside of the C:\Windows\System32 directory, it might not be the genuine nslookup.exe. In such a case, it’s highly recommended to run a full system scan using a reliable antivirus software. If the file is flagged as malicious, the antivirus software will handle its removal.


In conclusion, nslookup.exe is a legitimate, harmless utility integral to the Microsoft Windows operating system. This utility is primarily used for querying the Domain Name System (DNS), translating human-readable domain names into machine-friendly IP addresses, which is crucial for navigating the internet.

However, if you’re experiencing issues such as frequent appearances of the nslookup.exe command window or high CPU and memory usage, it might indicate underlying problems. These can range from simple network issues or misconfigurations to potential malware masquerading as nslookup.exe.

Troubleshooting methods like checking the Task Scheduler, monitoring Startup Programs, and using tools like Microsoft Sysinternals Procmon can provide useful insights to resolve these issues. Always ensure your system’s security by regularly scanning for malware and keeping your antivirus software up to date.

Nyau Wai Hoe
Nyau Wai Hoe is the Founder and Chief Editor of WindowsDigitals.com. With a degree in software engineering and over 12 years of experience in the tech support industry, Nyau has established himself as an expert in the field, with a primary focus on the Microsoft Windows operating system. As a tech enthusiast, he loves exploring new technologies and leveraging them to solve real-life problems.

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