What is ndis?

Ndis.sys is a Windows driver. A driver is a small software program that allows your computer to communicate with hardware or connected devices. This means that a driver has direct access to the internals of the operating system, hardware etc. The free file information forum can help you determine if ndis.sys is a Windows system file or if it belongs to an application that you can trust.

Run a free scan to check for ndis drivers in need of updating

Ndis.sys file information

The process known as NDIS 5.1 wrapper driver or NDIS 6.20 driver belongs to software Microsoft Windows Operating System or Betriebssystem Microsoft Windows by Microsoft (

Description: The original ndis.sys is an important part of Windows and rarely causes problems. Ndis.sys is located in the C:\Windows\System32\drivers folder. Known file sizes on Windows 10/8/7/XP are 182,656 bytes (47% of all occurrences), 182,912 bytes, 527,848 bytes, 500,840 bytes or 161,536 bytes. 
The driver can be started or stopped from Services in the Control Panel or by other programs. The file is a Windows core system file. The program is not visible. There is no detailed description of this service. It is a trustworthy file from Microsoft. ndis.sys appears to be a compressed file. Therefore the technical security rating is 2% dangerous; however you should also read the user reviews.

Uninstalling this variant: If you still experience problems with ndis.sys, you can uninstall Microsoft Windows from your computer using the Control Panel applet Uninstall a Program or visit the website.

Recommended: Identify ndis.sys related errors

Important: Some malware disguises itself as ndis.sys, particularly when not located in the C:\Windows\System32\drivers folder. Therefore, you should check the ndis.sys process on your PC to see if it is a threat. We recommend Security Task Manager for verifying your computer's security. This was one of the Top Download Picks of The Washington Post and PC World.


User Comments

All i know is my computer crashes all the time, it enters a blue screen with some weird error, In the**Stop** error it said "ndis.sys"
  Double Helix  
When you change the IPX frame type for your network connection from Auto Detect to any other IPX frame type, you may receive a "STOP 0x0000001D" or "STOP 0x000000A" Stop error that occurs in Ndis.sys.
  narrowgate   (further information)
I've got the same problem if i play pcgames!... after a time a blue screen apperas with the text ndis.sys problem or sth like this.. and is had to turn off my computer
The upgrade of WinXP to Service Pack 2 needs this file (in system32/drivers) to no longer be in use, but it always is.
Windows XP HE will not start if ndis.sys is missing/quarentined. Startup will go into a loop , a blue screen will flash (too quick to read), and PC will go to boot again and stop to ask how windows should be started. (Blue screen actualy says: Windows has detected a problem and will shot down to protect your PC) . Because you can not start windows is very difficult to fix. You will need your windows CD and probably need to use the XP recovery console
  George Vides  
It is sometimes replaced with a Trojan in the folder and moves the Microsoft Ndis to a different folder.
I had the same issue and it ended up being a bad onboard NIC. I just disabled it in the BIOS and chose 'last known good' to boot to and it worked. I then installed a NIC PCI card and got network connectivity back up.
I currently (4/23/09) have a system running Win XP SP3 and the AV software reports NDIS.sys and denies access. I am pretty sure the file is infected, since I have been removing viruses and trojans the past few days, but this problem is pretty persistant. Also I get the 'blue' screen when running 'superantispyware' which normally is a great piece of software to remove all kinds of malware. I can not remove the file since it is in use (not even in safe mode). I do belive NDIS.sys is a windows critical file, but it is hijacked be some piece of malware.
causes my pc blue screen
ndis.sys is a network layer driver crucial for network interface controllers that access the internet
hash for ndis.sys file should be: md5 1DF7F42665C94B825322FAE71721130D
  jambalaya   (further information)
In my case, this file was infected with Win32/Protector.C virus as NOD32 said. After deleting the file, nothing happened, but after the next restart, WinXP coudn't start some services including RPC and WZC (wireless zero configuration). After restoring the file, I tried to start the service, but the Windows crashed, and after the restart, the network connection worked again.
erzeugt ständig bluescreen
If you're getting blue screens for NDIS.sys put in your windows disk and run the following command from command prompt (copy & past) "del %windir%\system32\drivers\ndis.sys expand e:\i386\ndis.sy_ %windir%\system32\drivers\ndis.sys"
yelloe icon on driver adapter
network problem
Some malware or virus infects it, and when disinfecting, ndis disappears thus disabling networkcards.
my dell m1330 wont start because ndis.sys missing/corrupt
NDIS.sys on my computer tries to access the Internet. I have my firewall block it's access but do not delete the file. Everything works OK that way.
  Ray B.  
it is related to networking
Required by ALL NT based versions of Windows. Most likely cause of Blue Screen relating to ndis.sys is due to a malfunctioning Norton product or an incorrectly/insufficiently uninstalled Norton title. Run "Norton Removal Tool" in Safe Mode to cure.
this file identify your network adapter and is very important file ,if u have problem with this file just delete this file and have a same copy from a working computer , paste it in c:windows/ system32/driver's folder , this will idnetify network adaptor .
that it make my pc get blue scrren
ndis.sys may be a symptom. I found that by changing my LAN socket on the modem and changing the LAN cable, I was able to resolve my problem. Don't discount the age of the cable. They are mass produced and new ones are not always perfect.
  The Doctor  
when i try to set up with internet it shows me this"driver_irql_nomatch_or_less(ndis.sys)"
  Dhrumil barot  

Rating chart

Summary: Average user rating of ndis.sys: based on 29 votes with 25 user comments. 16 users think ndis.sys is essential for Windows or an installed application. 4 users think it's probably harmless. 4 users think it's neither essential nor dangerous. 2 users suspect danger. 3 users think ndis.sys is dangerous and recommend removing it. 6 users don't grade ndis.sys ("not sure about it").

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Best practices for resolving ndis issues

A clean and tidy computer is the key requirement for avoiding problems with ndis. 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.

To help you analyze the ndis.sys process on your computer, the following programs have proven to be helpful: ASecurity Task Manager displays all running Windows tasks, including embedded hidden processes, such as keyboard and browser monitoring or Autostart entries. A unique security risk rating indicates the likelihood of the process being potential spyware, malware or a Trojan. BMalwarebytes Anti-Malware detects and removes sleeping spyware, adware, Trojans, keyloggers, malware and trackers from your hard drive.

Other processes

ndis.sys [all]