How to Fix Mmsystem.dll Errors

Mmsystem.dll is a module that manages multimedia for 16-bit multimedia applications.

Here are some errors that are related to mmsystem.dll. The method to resolve the issues that are causing these errors also follow.

Error Message:

Rundll32 - This program has performed an illegal operation and will be shut down.

Rundll - This program has performed an illegal operation and will be shut down.

Mmsystem.dll may cause random general protection fault error messages, as well as the error messages shown above.

If you click on the Details button, you will get a message similar to the ones listed below:

RUNDLL32 caused a General Protection Fault in module MMSYSTEM.DLL

RUNDLL caused a General Protection Fault in module MMSYSTEM.DLL at 000a:00000032

Errors relating to mmsystem.dll are usually seen by the use of the Add New Hardware option in the Control Panel.


This error occurs when the drivers=mmsystem.dll line is missing from the boot section of the system.ini file.


How to Fix Mmsystem.dll General Protection Error

  1. Use the Search function to locate System.ini on your computer.
  2. Use Notepad or any text editor to open up the System.ini file.
  3. Add the following line to the boot section of the file.drivers=mmsystem.dll
  4. Save and exit.
  5. Restart your computer.


System.ini has been replaced by system.cb


Please note:? this command will not work if you do not have system.ini in your PC.

How to fix system.ini replacement error

  1. Open the Command Prompt window.
  2. Enter the following commands:ren system.ini system.bak
  1. copy system.cb system.ini
    edit system.ini
  2. A text editor will open.
  3. Press Enter at the beginning.
  4. Hitting Enter moves the cursor to a blang line.
  5. Add the following lines to the system.ini file[boot]
  6. Move to the section that begins with [386Enh].
  7. Add the following line just right below the heading:mouse=*vmouse


Computer stops responding after the installation of Windows Millennium Edition. Restarting in Safe Mode produces a blank Desktop devoid of icons or taskbar.

Error Message:

msgsrv32 has caused an error in mmsystem.dll


A damaged Setupx.dll file can cause this error.


  1. Click on Start and then go to Search.
  2. Click For Files and Folders.
  3. Type setupx.dll in the Search for files or folders named box.
  4. Select Local Hard Drives in the Look box.
  5. Press Enter and wait for the search results.
  6. Right click on Setupx.dll.
  7. Rename setupx.dll to setupx.old.
  8. Enter.
  9. Extract a new copy of Setupx.dll file to your computer.

You may find more information on how to extract original compressed Windows files in this article.

Error Message:

An error has occurred in your program. To keep working anyway, click Ignore and save your work to a new file. To quit this program, click Close. You will lose information you entered since your last save.

Explorer This program has performed an illegal operation and will be shut down. If the problem persists, contact the program vendor.

You may receive the first error message if the Start button is clicked while the Startup sound is playing. Clicking ignore will just repeat the message.

Clicking Close will produce the second error message shown above.

Details for these error messages will display the following information:
EXPLORER caused a general protection fault in module mmsystem.dll at 0004:xxxxxxxx

The Active Desktop Recovery Screen may appear if you are using Active Desktop. Restore My Active Desktop may restore your Active Desktop settings but the icons on the right side of the taskbar may not be present until restart.


If you have Naleco RADFind 96 version 1.0a installed and your Menu Popup and Windows Start events sounds are .wav files, the error message will come up when the Start button is clicked. This is because RADFind 96 is scanning your disk.


There are several methods for resolving this issue. Choose a method that is appropriate for your need.

Method 1

  1. Click Start and go to Settings.
  2. Click Control Panel.
  3. Double click the Sounds icon.
  4. Click Menu Popup in the Events box.
  5. Click None for the Sound box.
  6. Press OK.

This will disable your sound for the Menu Popup event.

Method 2

Do not click the Start button until:

  • The Windows Startup sound is done
  • RADFind 96 has finished scanning your drives

Method 3

Uninstall RADFind 96.

You can use Perfect Uninstaller to remove RADFind 96 from your system. You may also remove the program using the Add/Remove option in Control Panel.