What is iaStor?

The genuine iaStor.sys file is a software component of Intel Application Accelerator Driver by Intel Corporation.
The "iaStor.sys" driver is part of the Intel Application Accelerator which must be installed when the computer is first configured. It enables using two or more hard disks in a Redundant Array of Inexpensive Disks (RAID) configuration. If "iaStor.sys" is stopped or uninstalled all data on any disks involved will be lost, which may include the Windows OS. The computer must have a supported chipset configuration, (including an Intel RAID option ROM chip) and the right kind of hard disks. "iaStor.sys" is one of six modules that must be installed twice, (first through BIOS at system setup and then reinstalled when in Windows), including "iaStor.inf" and "," in order to use RAID disk management logic. Intel Corporation, an American multinational semiconductor manufacturer based in Santa Clara, CA, USA, is the world's largest and highest valued.

IAStor stands for Intel SATA Storage Device RAID Controller

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

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

IaStor.sys file information

The process known as Intel Matrix Storage Manager driver (version ia32, x64) or Intel Rapid Storage Technology driver (version x64) or Intel AHCI Controller or Intel Application Accelerator driver belongs to software Intel Matrix Storage Manager driver or Intel RAID Controller or Intel AHCI Controller or Intel Rapid Storage Technology driver by Intel (

Description: IaStor.sys is not essential for the Windows OS and causes relatively few problems. The iaStor.sys file is located in the C:\Windows\System32\drivers folder. Known file sizes on Windows 10/8/7/XP are 874,240 bytes (29% of all occurrences), 872,064 bytes and 8 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. IaStor.sys is not a Windows core file. The iaStor.sys file is a Microsoft signed file. iaStor.sys appears to be a compressed file. Therefore the technical security rating is 21% dangerous, however you should also read the user reviews.

Recommended: Identify iaStor.sys related errors

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

If you have RAID configuration do not remove file!
  Roni   (further information)
This file was made by Intel to give Windows more access to the harddrive. It is a file that Dell machines will request upon an installation of windows xp.
iastor.sys is the intel matrix storage manager driver file. You may be able to start and stop it but once windows loads it's always running anyways if you have a HDD controller that needs it.
  Mike   (further information)
Windows XP needs it so instal.
  Adam Ehrman Shapiro  
necessary file as it blocks windows from starting up when damaged
Intel Application Accelerator RAID Edition
IASTOR.SYS is a driver used to control the SATA disks, usually for raid systems but still used in normal single disk setups as well. It should NOT be removed.
HP Pavilions also affected
  Lance Vannorsdel  
I just deleted mine on the same error and now i am unable to reach the windows log on screen befor it bsod on me
  B money  
if you want to re- instal windows you got to have this file, or else your setup will freeze
System blue screene while running audit32 for trackit
IAStor.sys is bei Intel Chipsätzen für die Ansteuerung der Festplatten bzw. anderer Massenspeichergeräten am IDE/SATA Controller notwendig
  Gonscho   (further information)
When I searched on iastor I found the file in windows/system32/drivers was not the same size as the oem store. I deleted it copied and paste the oem version and everything is now OK.
  Robin Harris  
Intel Storage System
boot divice
  abdull moosa  
Go to search iastor.sys download newest driver. Intel® Matrix Storage Manager version 8.8
    (further information)
The same thing happened to me when I wanted to reload the XP Home. I asked the friends who are specialists on the computers and they checked if loading is possible without the hard disk. Yes it was possible and they decided that the hard disk is defective. So I bought a new hard disk and reloaded all the softwares I needed. But it has been out of order aftr one day. So I tried the old one again while I sent the new one for service. I removed almost all the programs from the hard disk and tried...Yes it was successful. Now I am using the old defective one on my laptop while waiting the new one.
  Hasan Akyüz  
it is intel sata/raid controler driver, it is very needed
it is SATA driver
Intel SATA RAID driver.
  Scottie B  
SATA drive controller file
install windows xp on sata hdd
  Hanif Salyani  
Since it is necessary, it's a target for infection by some Trojan type viruses, such as Tidserv. Your computer may not boot if it is removed, even into safe mode, if you remove it, and if infected it cannot be cleaned or unloaded by Symantec Endpoint Protection. I would replace the file with a clean version from an uninfected computer.
  Random computer repair guy   (further information)
It's a SATA driver
Very important file; run malwarebytes to check for infection if in doubt, otherwise don't touch.
In addition to Dell problems (see link) the file may not be called due to Win32/Patched.CJ Trojan
  Nan   (further information)
I had to repair install my Windows xp and it asked for this file. O cancelled because I didn't know where it was and Windowd wouldn't boot. I reinstalled and found the location through this site and Windows installed. This file is definitely needed.
  I. Patel  
Intel RAID/AHCI Treiber
iaStor.sys is an essential file to your computer, if you have it. It's all part of the RAID/ICH system and if you have a laptop with Sigmatel Sound, ICH is critical and necessary for the sound to work. Don't know why? However, if your RAID/ICH is messed up, you may have to re-install XP or you may have to remove AHCI and other things first and re-install your RAID/ICH first before re-installing the other system functions such as the AHCI. Search Google for more info on how you can fix this. I am still working on it myself but I am finding it should not be disabled or removed! This is an Intel product made for Dell. If it's on your system, don't try to disable it. For things to work correctly again, it may need to be fixed or re-installed.
  Dell User  
This file is core for Windows. I may say from firsthand experience that without this file intact, Windows Seven will BSOD, making for a difficult workaround situation when no external media [i.e. valid install CD] is present.
It is linked in with SATA and the hard drives, without it your machine is unlikely to boot.
Not found at all in my XP SP3 32-bit system running in IDE mode. Think it is needed in AHCI mode
a link to a clean copy is what's needed here on this page.
My computer will crash after ~20 minutes of inactivity regardless if there's a screensaver running, and iastor.sys is always mentioned in the .dmp
Get kapersky task killer run from safemode it will fix the iastor.sys BSOD
  Chay chauncey  
its the SATA drive config file!
  John   (further information)
Sure you can boot, & surely the PC will run wonderful without it. I ran my PC for weeks, with an Asus MB, Intel i7 2600K. The problem started when I turned on the AHCIP in the BIOS, only then window asks for the "PCI" file. My PC crashes BSOD when I try to load it. So I run without it until Intel fixes their driver. The same driver is used on all intel chipsets (not only on Dell as said above). It's a very poorly written software driver, Over 8,000 complaints from DELL customers alone. + thousands more.You can run Windows without it (not essential, but you may not be able to run in RAID.
Keep getting BSoD from it!
Causes BSOD when Windows defender scans for malware
Mine isstor.sys BSOD was a trojan. Ran micosoft security scanner and Malware Bytes to remove. This was a backdoor trojan so, unfortunately Security Essentials didn't detect it
I cannot install windows XP P ro witout it.
Windows Repair Tools were indicating this file was corrupt. After reading other comments I deleted iastor.sys and eventually iastorV.sys as well (by renaming the files to *.old). Haven't had any problems since. Elected to remove the software which was optional anyway (came with Gigabyte motherboard).
This file can be infected by a virus
causes BSOD
Just uninstall and reinstall the IRST driver
Because of iastor errors, I have had to rebuild my PC 4 times in 6 months.
Came with Windows 7 Professional on an HP Z800 Workstation, so I would assume it is mission-critical. It eats up 20% of my 2x Hex Core CPU's though.

Rating chart

Summary: Average user rating of iaStor.sys: based on 67 votes with 47 user comments. 46 users think iaStor.sys is essential for Windows or an installed application. 11 users think it's probably harmless. 3 users think it's neither essential nor dangerous. 2 users suspect danger. 5 users think iaStor.sys is dangerous and recommend removing it. 9 users don't grade iaStor.sys ("not sure about it").

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Best practices for resolving iaStor issues

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

iaStor.sys [all]