What is ACPI?

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

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ACPI.sys file information

The process known as ACPI Driver for NT or Microsoft ACPI Driver belongs to software Microsoft Windows Operating System by Microsoft (

Description: The original ACPI.sys is an important part of Windows and rarely causes problems. ACPI.sys is located in the C:\Windows\System32\drivers folder. Known file sizes on Windows 10/8/7/XP are 187,776 bytes (42% of all occurrences), 274,304 bytes and 6 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 service has no detailed description. It is a trustworthy file from Microsoft. ACPI.sys appears to be a compressed file. Therefore the technical security rating is 6% dangerous, however you should also read the user reviews.

Uninstalling this variant: If you have any problems with ACPI.sys, you may also uninstall the associated program (Start > Control Panel > Uninstall a Program > Microsoft Windows) or visit the website.

Recommended: Identify ACPI.sys related errors

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

makes our servers crash
automatica configuration power interface
Belongs to Microsoft Windows Operating System. ACPI Driver for Windows NT.
working of this file
Automatic Configuration Power Interface is a driver which will attempt to throttle CPU usage when temperatures get to high (and other power management operations)
  Chuck   (further information)
It is the interface between outside vendors and proprietory Windows Management Instrumentation. Can't leave home without it.
  Stephen   (further information)
takes up CPU resources when running 3D applications on some laptops
when i try to reinstall windows it says "acpi.sys corrupted". how to fix it
Lots -- by accident! This error message = defective RAM. Replace and, voila, your laptop will spark right up.
ACPI is an open standard specification introduced by industry to allow operating systems to "discover" hardware and manage power resources. It is what allows "sleep mode" and "wake on key" as well as other energy management processes. acpi.sys is Windows system driver that handles these processes.
  Elektronik_1   (further information)
nothing.. firefox was installed and reinstalled the latest update caused our pc to crash numerous times
I am investigating a virus which through AVG incorrectly states that acpi.sys is carrying a virus. Not sure of why at this stage
  Henry M  
Fingala redirection infects it and stops google working. Tdskiller.exe from Kaspersky fixed it.
Windows file needed for proper boot up.
I have the same issue with AVG, wanted to move the acpi.sys to a quarantine folder.
removed with spybot1.6.2, damaged chrome and IE, redirection to clone website, damages SSL connections and installs other malware like browser pop-ups

Rating chart

Summary: Average user rating of ACPI.sys: based on 21 votes with 16 user comments. 13 users think ACPI.sys is essential for Windows or an installed application. 5 users think it's probably harmless. One user thinks it's neither essential nor dangerous. 2 users think ACPI.sys is dangerous and recommend removing it. 6 users don't grade ACPI.sys ("not sure about it").

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Best practices for resolving ACPI issues

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

ACPI.sys [all]