What is pci?

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

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

Pci.sys file information

The process known as NT Plug and Play PCI Enumerator belongs to software Microsoft Windows Operating System or PCI Bus Driver by Microsoft (

Description: The original pci.sys is an important part of Windows and rarely causes problems. Pci.sys is located in the C:\Windows\System32\drivers folder. Known file sizes on Windows 8/7/XP are 68,224 bytes (75% of all occurrences), 68,608 bytes, 68,736 bytes, 151,096 bytes or 62,976 bytes. 
The driver can be started or stopped from Services in the Control Panel or by other programs. The file is a Windows system file. The program has no visible window. Pci.sys is a Microsoft signed file. There is no detailed description of this service. pci.sys appears to be a compressed file. Therefore the technical security rating is 3% dangerous, however you should also read the user reviews.

Recommended: Identify pci.sys related errors

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

everytime i installing my windows xp, this pci.sys. comes out
It is a system file
  Amit kumar  
I am getting error related to this file while installing my OS
It can cause problems with newer hardware. Particularly those wth PCIe ports. The solution is to use XP SP2 and above or a modern OS.
How to fix "Pci.sys Is Missing or Corrupt" Error Message When You Start Windows, see link
  Matt   (further information)

Summary: Average user rating of pci.sys: based on 5 votes with 5 user comments. 4 users think pci.sys is essential for Windows or an installed application. One user thinks it's probably harmless.

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Best practices for resolving pci issues

A clean and tidy computer is the key requirement for avoiding problems with pci. 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 doing a repair of your installation, or in the case of Windows 8, 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 pci.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

pci.sys [all]