What is Rundll32.dll?

Rundll32.dll is a Windows DLL file. DLL is the abbreviation for Dynamic Link Library. DLL files are needed by programs or web browser extensions, because they contain program code, data, and resources. The following information can help you determine if Rundll32.dll is a Windows system file or if it belongs to an application that you can trust.

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Rundll32.dll file information

The process known as Application appears to belong to software Microsoft by Microsoft (

Description: Rundll32.dll is not essential for Windows and will often cause problems. Rundll32.dll is located in the C:\Windows\System32 folder. The file size on Windows 10/8/7/XP is 81,920 bytes. 
A .dll file (Dynamic Link Library) is a special type of Windows program containing functions that other programs can call. This .dll file can be injected to all running processes and can change or manipulate their behavior. There is no file information. The program has no visible window. There is no detailed description of this service. It can change the behavior of other programs or manipulate other programs. The file is not a Windows core file. Therefore the technical security rating is 82% dangerous, however you should also read the user reviews.

Recommended: Identify Rundll32.dll related errors

Important: Some malware also uses the file name Rundll32.dll, for example Hacktool or Trojan Horse (detected by Symantec), and Tool:Win32/SqlCrack or Trojan:Win32/Opachki.A (detected by Microsoft). Therefore, you should check the Rundll32.dll 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

rundll32.dll is malware that camouflage itself as windows file rundll32.exe
  Ann   (further information)
rundll32 wird u.a. für das manuelle starten von .dll dateien gebraucht
windows media player run on this dll
it clones itself 10's of times
  Bill Schoenfeld  

Summary: Average user rating of Rundll32.dll: based on 4 votes with 4 user comments. One user thinks Rundll32.dll is essential for Windows or an installed application. One user thinks it's probably harmless. 2 users think Rundll32.dll is dangerous and recommend removing it. One user is not sure about it.

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Best practices for resolving Rundll32 issues

A clean and tidy computer is the key requirement for avoiding problems with Rundll32. 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 repairing of your installation or, for Windows 8 and later versions, 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 Rundll32.dll 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

Rundll32.dll [all]