Like with most of the .exe files, you will find rundll32.exe also running in the task manager without having been placed there. Those of you are die-hard users of Windows must have seen innumerable *.dll files in all the application folders.
These folders act as storage for customary logical applications that can be opened using various other applications.
A .dll file stands for Dynamic Link Library.
A dynamic link file cannot be run directly. Hence, it uses the rundll32.exe process for launching itself. The process is an in-built feature of the Windows and does not pose any harm to the machine or software.
Windows Vista’s Task Manager and rundll32.exe
The Task Manager of Windows Vista is able to detect the complete command line that is being used to run any application or process.
You can check the command by going to the View/Select Columns. Here you will find the “Command Line” option in the list. This list will give you the command prompt for all the applications that are currently running.
The list will also give you the entire path for the application or process. The legit path for rundll32.exe is in the directory of System 32.
Now go the Properties and check the Details option. You will find the entire description for the file here. You will also find an apt explanation for the existence of the file.
Once you know the reason for the installation of the file/process, you can decide for yourself whether you want to keep it or disable it.
In case you still aren’t sure, then go to a public forum and take help from someone who knows the ins and outs of what you are asking.
Vista, XP and rundll32.exe
In case of Windows Vista and XP we can use Process Explorer instead on Task Manager. The Process Explorer also lets you know the steps that are being performed.
You will have to first launch the Process Explorer. In case of Vista, go to File and then select the ‘Show Details for All Processes’ tab.
Flicker the mouse over rundll32.exe when it appears in the list. This will give you a tooltip as well as information about the process.
How to Disable the Process?
The process is quite harmless and there is no need to disable it. However, if you still wish to, you will have to go to the Start Menu and type in msconfig.exe in the search box and press ENTER. You will receive a Command column that should match with the “Command Line” field given in the Process Explorer. Unchecking the box will prevent the process from running automatically.
In some cases the process need not necessarily have a startup item. If this happens you will have to some exhaustive research to find out the place of the origin of the process. For example, opening the Display Properties in Windows XP will show you rundll32.exe under the list. The reason for this is that the Windows employs the rundll32 functionality to start a dialog.