REGSVR32 is a command-line utility in Windows that registers and unregisters DLL (Dynamic Link Library) and ActiveX controls in the system registry. This command is primarily used by developers and system administrators to enable or disable certain functions, components, or applications that rely on these libraries.


The basic syntax of REGSVR32 is as follows:

REGSVR32 [/u] [/s] [/n] [/i[:cmdline]] dllname


  • dllname: Specifies the path and filename of the DLL or ActiveX control you want to register or unregister.


  • /u: Unregisters the specified DLL.
  • /s: Runs the command silently, with no message boxes.
  • /n: Does not call DllRegisterServer; when combined with /i, it calls DllInstall.
  • /i: Calls DllInstall passing it an optional [cmdline]. When used alone, this option calls DllRegisterServer unless /n is specified.


  • /u: Use this option to unregister DLLs. It is commonly used to disable outdated or malfunctioning system extensions without deleting the file.
  • /s: This silent mode is useful in scripts or batch operations where user interaction or pop-ups are undesirable.
  • /n: This rarely used option prevents the DllRegisterServer function from being called, which normally would register the DLL. Typically, it’s used with /i for special installation setups.
  • /i:[cmdline]: Provides a custom command line to DllInstall, allowing more flexibility during registration if the DLL supports additional setup options.


  1. Register a DLL:

    REGSVR32 shmedia.dll

    This command registers the shmedia.dll, enabling its functionalities within the system.

  2. Unregister a DLL:

    REGSVR32 /u shmedia.dll

    Use this command to unregister shmedia.dll, which might be necessary if it’s causing conflicts or errors.

  3. Silent registration of a DLL:

    REGSVR32 /s mycom.dll

    Registers mycom.dll without any confirmation dialogues or pop-ups, suited for automated scripts.

  4. Register a DLL with custom command line options:

    REGSVR32 /i:setup /n mysetup.dll

    This runs DllInstall instead of DllRegisterServer, passing setup as an argument to mysetup.dll.

Common Issues

  • Missing DLL Errors: Make sure the DLL exists in the specified path. If the file is missing, restore it or verify the installation source.
  • Permission Issues: Running REGSVR32 might require administrative privileges especially when making changes to the system registry.
  • Compatibility Issues: Some DLLs are made for specific versions of Windows. Ensure compatibility between your DLL and your Windows version.


Example Batch Script to Register Multiple DLLs:

@echo off
SETLOCAL EnableDelayedExpansion
FOR %%A IN (*.dll) DO (
    REGSVR32 /s %%A

This script registers all DLLs in the current directory silently, useful for initial setup or deployment scenarios.

  • DLL files: They contain code and data that multiple programs can use simultaneously.
  • ActiveX controls: Similar to DLLs but can be used in a variety of applications, especially within web browsers.

For further information, refer to Microsoft’s official documentation on their MSDN website.