What is NISShExt.dll?

NISShExt.dll is a browser extension for Internet Explorer. This add-on enables several additional functions for Internet Explorer. You can disable it through the Extras menu (key combination Alt + X) under Manage Add-ons. The following paragraph provides more information about NIS Shell Extension.

Click to Run a Free Scan for NISShExt.dll related errors

NISShExt.dll file information

The process known as NIS Shell Extension belongs to software Norton Internet Security or Internet Security by Symantec (

Description: NISShExt.dll is not essential for the Windows OS and causes relatively few problems. NISShExt.dll is located in a subfolder of "C:\Program Files\Common Files"—mainly C:\Program Files\Common Files\Symantec Shared\AdBlocking\. Known file sizes on Windows 10/8/7/XP are 126,976 bytes (45% of all occurrences), 103,568 bytes and 4 more variants. 
This .dll file is a Browser Helper Object (BHO) that runs automatically every time you start your web browser. BHOs are not stopped by personal firewalls, because they are identified by the firewall as part of the browser itself. BHOs are often used by adware and spyware. IDs used by this BHO include 9ECB9560-04F9-4bbc-943D-298DDF1699E1. The program has no visible window. The NISShExt.dll file is able to monitor web browsers. NISShExt.dll is not a Windows core file. You can uninstall this program in the Control Panel. Therefore the technical security rating is 38% dangerous, however you should also read the user reviews.

Uninstalling this variant: You could safely remove the program using the uninstall program of Norton Internet Security (Control Panel ⇒ Uninstall a Program).

Recommended: Identify NISShExt.dll related errors

External information from Tony Klein:

Important: Some malware camouflages itself as NISShExt.dll, particularly when located in the C:\Windows or C:\Windows\System32 folder. Therefore, you should check the NISShExt.dll process on your PC to see if it is a threat. If NIS Shell Extension has changed your browser's search engine and start page, you can recover your browser's default settings as follows:

Reset default browser settings for Internet-Explorer ▾
  1. In Internet Explorer, press the key combination Alt + X to open the Tools menu.
  2. Click Internet options.
  3. Click the Advanced tab.
  4. Click the Reset... button.
  5. Enable the Delete personal settings option.
This will reset your Internet Explorer to its default settings. Your browser will start with the familiar start page and search engine—without popups, ads, cookies, but all browser add-ons are deleted too [1]. Make cleaning up your browser and your computer simpler and safer with Security Task Manager.


User Comments

This is Norton IS system file
Norton Internet Security ?
Norton Internet Security system file
Norton Internet Security
Norton Internet Security system file
Part of Symantec Norton Internet Security suite
  Georg   (further information)
Its a trojan that looks like norton, (i dont have norton or ever visited it site but i have it
Norton Internet Security file thats what it is
nis 2005
  j. alberto  
If you have NAV installed then it's NAV, otherwise you'r infected
Safe if it's in \Common Files\Symantec Shared\AdBlocking\
that it's good
  betty breedlove  
NISShExt.dll 2006

Rating chart

Summary: Average user rating of NISShExt.dll: based on 14 votes with 13 user comments. 9 users think NISShExt.dll is essential for Windows or an installed application. One user thinks it's probably harmless. 3 users think it's neither essential nor dangerous. One user thinks NISShExt.dll is dangerous and recommends removing it. One user is not sure about it.

Do you have additional information?
What do you know about NISShExt.dll:
How would you rate it:
Link for more info:
Your Name:

Best practices for resolving NISShExt issues

The following programs have also been shown useful for a deeper analysis: ASecurity Task Manager examines the active NISShExt process on your computer and clearly tells you what it is doing. Malwarebytes' well-known Banti-malware tool tells you if the NISShExt.dll on your computer displays annoying ads, slowing it down. This type of unwanted adware program is not considered by some antivirus software to be a virus and is therefore not marked for cleanup.

A clean and tidy computer is the key requirement for avoiding PC trouble. This means running a scan for malware, cleaning your hard drive using 1cleanmgr and 2sfc /scannow, 3uninstalling programs that you no longer need, checking for Autostart programs (using 4msconfig) and enabling Windows' 5Automatic Update. Always remember to perform periodic backups, or at least to set restore points.

Should you experience an actual problem, try to recall the last thing you did, or the last thing you installed before the problem appeared for the first time. Use the 6resmon command to identify the processes that are causing your problem. Even for serious problems, rather than reinstalling Windows, you are better off repairing of your installation or, for Windows 8 and later versions, executing the 7DISM.exe /Online /Cleanup-image /Restorehealth command. This allows you to repair the operating system without losing data.

Other processes

NISShExt.dll [all]