What is rasacd?

The genuine rasacd.sys file is a software component of Remote Access Automatic Connection Driver by Microsoft.
"Rasacd.sys" is a Windows dynamic link library kernel driver and is known as the Remote Access System (RAS) Automatic Connection Driver, which handles remote connections for various third-party programs that are running. The file is a core driver within Windows Operating Systems, designed to implement certain actions within the OS in conjunction with the third-party software that uses it. It is basically a file that is already in the OS that other programs can utilize to ensure they work properly within the OS. Programs can include anti-virus software, online games, and much more. This driver is part of several RAS drivers that are utilized by other programs within Windows, such as 'rasl2tp.sys' RAS L2TP mini-port/call-manager driver and 'raspptp.sys' Peer-to-Peer Tunneling Protocol. The file is susceptible to virus infections, which is often indicated by the consumption of 90% or more of system resources, while also redirecting Google searches. Microsoft is a global leader in technological devices and software. With their leading operating systems and extensive applications, they paved the way to PC collaboration and worldwide standard usage.

RASACD stands for RAS Automatic Connection Driver

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

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

Rasacd.sys file information

The process known as RAS Automatic Connection Driver belongs to software Remote Access Auto Connection Driver by Microsoft (

Description: Rasacd.sys is an important part of Windows, but often causes problems. Rasacd.sys is located in the C:\Windows\System32\drivers folder. Known file sizes on Windows 10/8/7/XP are 8,832 bytes (92% of all occurrences) or 11,776 bytes. 
The driver can be started or stopped from Services in the Control Panel or by other programs. It is a Windows core system file. The program is not visible. The rasacd.sys file is a trustworthy file from Microsoft. rasacd.sys appears to be a compressed file. Therefore the technical security rating is 1% dangerous, however you should also read the user reviews.

Recommended: Identify rasacd.sys related errors

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

Not a thing, that is why I came in here looking...
  Jeffrey S. Bohemier  
Variant of Alureon/TDSS rootkit, hard to detect with multiple protection software, HitmanPro (1-month free trial) detected and removed it.
  Kieran Mitchell   (further information)
rasacd.sys is part of Windows and is Microsoft Windows RAS automatic connection driver that should be located in the C:\Windows\System32\drivers.
windows xp detected presence in BSOD message on crash, accompanied by 'page fault in non-paged area' message. Zero access Trojan was discovered just prior to crash. A newly installed Firefox media plugin maybe the conduit.
  Des Tekki  

Summary: Average user rating of rasacd.sys: based on 4 votes with 4 user comments. One user thinks rasacd.sys is essential for Windows or an installed application. One user thinks it's probably harmless. One user thinks it's neither essential nor dangerous. One user thinks rasacd.sys is dangerous and recommends removing it. One user is not sure about it.

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Best practices for resolving rasacd issues

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

rasacd.sys [all]