What does the rundll32.exe file do?
The rundll32.exe process is also known as Run a DLL as an App or, as the case may be, Windows host process (Rundll32) and is a part of Microsoft Windows Operating System or, as the case may be, Lsz. This software is produced by Microsoft (www.microsoft.com) or, as the case may be, Ocf. An obsolete or defective version of rundll32.exe can cause problems for your computer that can range from slowness to error messages such as these:
- Run a DLL as an App has stopped working. Windows is checking for a solution to the problem... (Windows 10, 8, 7)
- Run a DLL as an App has stopped working. A problem caused the program to stop working correctly. Windows will close the program and notify you if a solution is available. (Windows 10, 8, 7)
- rundll32.exe has encountered a problem and needs to close. (Windows XP)
- Access violation at address FFFFFFFF in module rundll32.exe. Read of address 00000000.
Free PC Check
Scan your computer today at no charge with the Windows Repair Tool. This tool helps repair Windows and helps it run faster.
What you should know about rundll32.exe Run a DLL as an App
rundll32.exe is a Windows system file. Rundll32.exe is found in the C:\Windows\System32 directory.
Frequently occurring are file sizes such as 33,280 bytes (53% of all these files), 44,544 bytes as well as 19 other variants.
To verify its trustworthiness, Microsoft has provided it with an embedded certificate. This process does not appear as a visible window, but only in Task Manager. For this reason, 8% of all experts consider this file to be a possible threat. The probability that it can cause harm is high.
rundll32.exe is a system file used by Microsoft Windows, and appears in Windows Task Manager as a process named "Run a DLL as an App." However, some viruses or Trojans use the same file name in order to remain undetected (such as Trojan:Win32/Jetil or, as the case may be, TrojanSpy:Win32/Babonock.A (recognized by Microsoft), as well as Trojan.Gen or, as the case may be, WS.Reputation.1 (recognized by Symantec)).
To be really safe, you should scan your computer with two different anti-virus engines. You can use a free Anti-Malware scanner for this purpose.
Objectionable files with the same file name have the following characteristics:
- A rundll32.exe file has a 6% certainty of being dangerous if it is found in a subdirectory of C:\Windows. In this case, the file size is usually 44,544 bytes (89% of all these files), 51,200 bytes as well as 4 other variants. The file is a Windows system file. Rundll32.exe contains Microsoft's digital signature. This confirms its authenticity. The program executes in the background, and can only be terminated using Windows Task Manager.
- A rundll32.exe file has a 67% certainty of being dangerous if it is found in a subdirectory of "C:\Users\USERNAME". In this case, the file size is usually 120,992 bytes (16% of all these files), 24,576 bytes as well as 8 other variants. The rundll32 file is not part of the Windows operating system. This rundll32.exe process does not appear as a visible window, but only in Task Manager. There is no embedded description in this file. These days, this is rather unusual When Windows starts, this process is automatically started at the same time (Registry: MACHINE\Run, Run, User Shell Folders, DEFAULT\Runonce, DEFAULT\Run, MACHINE\RunOnce). Rundll32.exe is capable of interpret keystrokes, monitor other applications as well as modify other Windows tasks.
- A rundll32.exe file has a 45% certainty of being dangerous if it is found in in a subdirectory of the Windows Temp folder. In this case, the file size is usually 310,359 bytes (66% of all these files) or, as the case may be, 44,544 bytes.
- A rundll32.exe file has a 50% certainty of being dangerous if it is found in a subdirectory of "C:\Program Files". In this case, the file size is usually 359,936 bytes.
If you see this file on your hard drive or in Windows Task Manager, please make sure that it is not a malicious variant. It's a fact that many trojans try to cloak their true identity by calling themselves rundll32.exe. With the above information or by using tools like Security Task Manager you can determine if, in your case, the file is an undesirable variant.
What do other computer users say about rundll32?
|RunDLL32 is used to run DLLs as programs |
|For some reason this program is hung in background and is stopping certain programs from opening. |
| Multiple instances of RUNDLL32 may be running on your pc at one time. Some of these may or may not be the legitimate versions. (further information...) |
Summary: 155 users judge rundll32.exe to be an essential file that should not be touched. 19 users consider it harmless. However, 64 users consider this to be a suspicious process and would like to get rid of it. For this reason, 97 users have already deleted rundll32.exe. source: file.net
How to uninstall the program or Lsz
To remove Run a DLL as an App from your computer, please follow the manual instructions below or use an automatic uninstaller product.
- Click the Windows Start Button. You find it in the lower left corner of the taskbar.
- Type the word uninstall.
- Click Add or remove programs.
- Now locate the program or Lsz in the list of displayed applications.
- Click the program, and then click Uninstall.
How to tell if rundll32.exe (Run a DLL as an App) was uninstalled cleanly
After uninstalling, restart your computer. Then start Windows Explorer and see if there is still a folder with the name of the software under C:\Program Files. Be sure to check the Registry as well for remnants of Run a DLL as an App. To do this, start "Regedit", then look under "HKEY_LOCAL_MACHINE" > "Software" for Run a DLL as an App or the name of the producer. Always keep in mind that only a computer professional should ever directly delete entries in the Windows Registry.
What to do if a program does not uninstall
The easiest way to remove any kind of software cleanly and accurately is to use an uninstaller tool. Because the uninstaller automatically creates a backup, there is no risk of anything going wrong.
Last but not least
If Windows not working quite right for you, or if startup is taking a long time, or rundll32.exe is causing problems for you, a good Windows diagnostic tool may very well help. This is especially effective when it comes to older computers that have accumulated vast quantities of "garbage data" as the result of many software installs and uninstalls.