How to Fix Missing or Corrupted RUNDLL32.EXE

The Internet abounds with ineffective and complicated methods to repair or replace a missing or corrupted rundll32.exe. The most common suggestion is to use the Windows files checker (sfc /scannow). It would be nice if File Checker fixed the problem, but it doesn not. However, the simple solution presented below is known to work.

What is rundll32.exe?

Simply, rundll32.exe is a Windows program which loads into memory and executes routines contained within dynamic link library (.dll) files.

For example, when you click on "Change date and time settings", rundll32.exe loads the necessary code from the appropriate dynamic link library file. Another task which relies upon rundll32.exe is configuring how you want the Windows Search function to operate.

What goes wrong with rundll32.exe?

The most common problem with rundll32.exe is that becomes corrupted by malicious code (computer viruses, etc.) and/or it gets deleted or quarantined by your anti-virus software after it has been infected by malware.

Solution

The solution, one that's easy and has worked every time for me, is to find a good duplicate copy of rundll32.exe on your computer and use it to replace the bad or missing copy.

Here's how:

1. Launch Windows Explorer
2. Single click on drive C: to select it
3. Into 'Search', type rundll32.exe
4. Search will find several instances of rundll32.exe on your system
5. Look for a copy of rundll32.exe that is NOT in the folder C:\WINDOWS\SYSTEM32
6. Single click that file to select it
7. Press Ctrl-C, or right-click the file and then click 'COPY'
8. Still in Windows Explorer, navigate to and select the folder C:\WINDOWS\SYSTEM32
9. Press Ctrl-V, or right-click the folder and then click 'PASTE'
10. Restart Windows

This solution won't work if ALL the copies of rundll32.exe are missing or corrupted, but that's an unlikely situation.