What is symtdi?

Symtdi.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 symtdi.sys is a Windows system file or if it belongs to an application that you can trust.

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

Symtdi.sys file information

The process known as Network Dispatch Driver or SYMTDI belongs to software Symantec Security Drivers or Symantec Network Dispatch Driver by Symantec (

Description: Symtdi.sys is not essential for Windows and will often cause problems. Symtdi.sys is located in the C:\Windows\System32\drivers folder. Known file sizes on Windows 10/8/7/XP are 191,544 bytes (33% of all occurrences), 184,240 bytes and 5 more variants. 
The driver can be started or stopped from Services in the Control Panel or by other programs. The program has no visible window. The file is a Verisign signed file. It is certified by a trustworthy company. There is no detailed description of this service. Symtdi.sys is not a Windows system file. You can uninstall this program in the Control Panel. symtdi.sys appears to be a compressed file. Therefore the technical security rating is 9% dangerous; however you should also read the user reviews.

Uninstalling this variant: If you are having problems with symtdi.sys, you can also safely remove the program using the uninstall program of SymNet or Symantec Network Drivers (Control Panel ⇒ Uninstall a Program).

Recommended: Identify symtdi.sys related errors

If symtdi.sys is located in a subfolder of C:\Windows\System32\drivers, the security rating is 21% dangerous. The file size is 217,136 bytes (50% of all occurrences), 217,392 bytes, 361,392 bytes, 388,216 bytes or 369,784 bytes. The program is not visible. The file is a Verisign signed file. The file has a digital signature. The service has no detailed description. Symtdi.sys is not a Windows core file. symtdi.sys appears to be a compressed file.

Important: Some malware disguises itself as symtdi.sys, particularly when not located in the C:\Windows\System32\drivers folder. Therefore, you should check the symtdi.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

Part of Symantec Norton Internet Security suite
  Georg   (further information)
it caused my WinXP to crash with a blue screen
Its a core file used for Nortan Internet Security
Part of Symnatec Redirector
  Steve   (further information)
when i log on my computer blue screen crashes, the problem emantates from symtdi.sys
my computer keeps crashing in windows startup. this is one of the errors in my sytem log
  Richard Paulusma  
Frequent blue screen crashes; Dell crash tool incriminates symtdi.sys ver. which was installed by Norton Internet Security 2005
this files causing often crashs on W2k3 and W2k4SP4 Rollup1v2
  Mario Grunert  
Other applications try to modify symtdi - zone alarm notifies me of this.
  John L  
My XP SP2 went to blue screen crash by it
Symtdi.sys is part of the Symantec Internet Security suite of products, which is not supported on Server operating systems.
  Dave Dippenaar   (further information)
It's signed by Symantec. And the self contained description says "Network Dispatch Driver"
  Steve Mahoney  
Removing this file caused my system to crash. It restarted with no problems, but the file was running again, I don't use Norton, but this file must be necessary in computers that came with Norton.
I am yet to find a Dell system that doesn't crash under this. Whatever it does, it's impossible to find. This is a file of the ENTIRE Norton AntiVirus programs - Internet Security [Suite], etc. Unfortunately, after tracing the problem for months, I have not found a way of removing it except removing the entire Norton AntiVirus program. Either get another version (I haven't tried it with '07 yet) or just get a completely different anti-virus program. Delete ALL Norton programs through add/remove programs.
  Andrew Sabre  
known issue with reboot issues for laptops? either remove Norton or simply deny system error reboots by changing "Write debugging information" to "none" (for no dump), under Startup & Recovery settings, under System Properties.
caused blue screen on my new Dell WinXP Home
this file will show up in i386 folder, but is usually used as a Norton internet security suite file, after an uninstall of the suite and reinstall of avast, the problem went away. I don't have time to reinstall NAV or NSS (norton antivirus, norton security suite) to see if the problem comes back after the reinstall, but it is gone for now.
Part of the endless driver sets that get woven in when you install Symantec products
Symantec Network Dispatch Driver - Causes BSOD to W2K3 SP1 with SAV 9.0.3
  The Prodigal Son  
My XP SP2 went to blue screen crash by it
it was a dependancy for DHCP client service (?) WTH?
Causes BSOD. Boot from WinXP CD, enter the recovery utility and rename the file to symtdi.old. Boot normally and remove the Norton AV.
  Kfir Marshak  
This file gives an error "Invalid IP Address" equivalent to needs to be removed in the registry key and restart the PC to remove that error.
  Shiena   (further information)
it stopped my internet from attached itself as a dependancy for DHCP client, causing DHCP client to stop working, thus I had no IP address.
SYMTDI drivers would also cause probles with Network tunneling softwares for VPN solutions like Juniper SSL VPN ,this piece is called WSAM
  Sam Higens   (further information)
Norton Internet Security 2010 Symantec Network Dispatch Driver
It crashes on Vista, blue screen of Death. I had to delete it from C:windows/system32/drivers
it causes a blue screen of death when i log in

Rating chart

Summary: Average user rating of symtdi.sys: based on 24 votes with 30 user comments. 10 users think symtdi.sys is essential for Windows or an installed application. 4 users think it's probably harmless. 3 users think it's neither essential nor dangerous. 7 users suspect danger. 10 users don't grade symtdi.sys ("not sure about it").

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Best practices for resolving symtdi issues

A clean and tidy computer is the key requirement for avoiding problems with symtdi. This means running a scan for malware, cleaning your hard drive using cleanmgr and sfc /scannow, uninstalling programs that you no longer need, checking for Autostart programs (using msconfig) and enabling Windows' Automatic 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 resmon 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 DISM.exe /Online /Cleanup-image /Restorehealth command. This allows you to repair the operating system without losing data.

To help you analyze the symtdi.sys process on your computer, the following programs have proven to be helpful: Security 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. Malwarebytes Anti-Malware detects and removes sleeping spyware, adware, Trojans, keyloggers, malware and trackers from your hard drive.

Other processes

symtdi.sys [all]