What is stac97?

The genuine stac97.sys file is a software component of AC'97 Audio Controller with SigmaTel CODEC device driver by Freescale.
"stac97.sys" is a Windows driver for SigmaTel (Freescale) audio devices and is known as the AC'97 Audio Controller with SigmaTel CODEC device driver. It is also known as the Sigmatel C-Major STAC 9750 AC97 WDM Audio Driver. The file handles AC'97 audio processing for select sound cards and uses a codec device driver to handle format processing. SigmaTel was originally a 'System on a Chip' (SOC) company that developed electronic circuits, boards, and software for video and audio electronics. It sold the pc audio division in 2006 to Integrated Device Technology (IDT) and moved on to Audio/Video decoding and processing. In 2008, Freescale Semiconductor acquired SigmaTel and integrated the products into their own products and business.

STAC97 stands for SigmaTel AC'97

Stac97.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 stac97.sys is a Windows system file or if it belongs to an application that you can trust.

Run a free scan to check for stac97 drivers in need of updating

Stac97.sys file information

The process known as SigmaTel Audio Driver belongs to software AC'97 Audio Controller with SigmaTel CODEC device driver by SigmaTel (

Description: Stac97.sys is not essential for the Windows OS and causes relatively few problems. The stac97.sys file is located in the C:\Windows\System32\drivers folder. Known file sizes on Windows 10/8/7/XP are 264,440 bytes (33% of all occurrences), 263,608 bytes, 247,920 bytes, 273,168 bytes or 276,816 bytes. 
The driver can be started or stopped from Services in the Control Panel or by other programs. The program is not visible. There is no detailed description of this service. It is not a Windows core file. The stac97.sys file is a trustworthy file from Microsoft. stac97.sys appears to be a compressed file. Therefore the technical security rating is 22% dangerous, however you should also read the user reviews.

Recommended: Identify stac97.sys related errors

Important: Some malware disguises itself as stac97.sys, particularly when not located in the C:\Windows\System32\drivers folder. Therefore, you should check the stac97.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

it is the driver for sigmatel audio device
  jef slangen  
A driver for the SigmaTel C-Major audio codec -- it should be digitally signed by Microsoft if authentic, and should be in the sys32/drivers file
sound file
  Bilal Ashraf  
for windows firma digital
driver update

Rating chart

Summary: Average user rating of stac97.sys: based on 17 votes with 5 user comments. 16 users think stac97.sys is essential for Windows or an installed application. One user thinks it's probably harmless. One user is not sure about it.

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Best practices for resolving stac97 issues

A clean and tidy computer is the key requirement for avoiding problems with stac97. 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 stac97.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

stac97.sys [all]