REGSVR32.exe

Register or unregister OLE controls, such as DLLs and ActiveX controls in the Windows Registry.

Syntax
      REGSVR32 [/U] [/S] [/N] [/e] /I:[CmdLine] DLLName

Key

  CmdLine    An optional command line for DllInstall

  default    With no other options: Register server by calling DLLRegisterServer.

   /i:       Call DllInstall(TRUE,[cmdline]) to install the DLL.
             if the install was successful also call DLLRegisterServer.

   /n /i:    Call DllInstall to install the DLL, but do not call DllRegisterServer.

   /U        Unregister Server by calling DLLUnRegisterServer.

   /U /i:    Call DllInstall(FALSE,[cmdline]) to uninstall the DLL.
             if the uninstall was successful also call DLLUnRegisterServer.

   /U /n /i: Call DllInstall(FALSE,[cmdline]) to uninstall the DLL.
             but do not call DllUnRegisterServer.

   /s        Silent, do not display any dialogue boxes.

   /e        Silent, do not display a success message for DllRegisterServer (undocumented).

  DLLName    The path (absolute or relative) to the DLL to call the entry point on.
             This DLL is required to export the entry points that will be called depending
             on the selected option: DLLRegisterServer, DLLUnRegisterServer or DLLInstall.

Regsvr32 requires Elevation.

ActiveX controls are now deprecated and will only run in Internet Explorer.

DllInstall is used only for application installation and setup. It should not be called by an application.
DllRegisterServer Instructs an in-process server to create its registry entries for all classes supported in the module.
DllUnregisterServer Instructs an in-process server to remove only those entries created through DllRegisterServer.

If you run REGSVR32 dllname.dll when the file is already registered, this will display a Pop Up message: "The module ModuleName was loaded but the Entry-point DllRegisterServer was not found."

On a 64-bit version of Windows Operating System, there are two versions of the Regsvr32.exe file:

The 64-bit version is %systemroot%\System32\regsvr32.exe
The 32-bit version is %systemroot%\SysWoW64\regsvr32.exe

To use the 32-bit version of Regsvr32 to register a 32-bit DLL on a 64-bit version of Windows, Open an elevated prompt and run a command like:

%systemroot%\SysWoW64\regsvr32 full_path_of_the_DLL

Examples

Unregister (Disable) CAB file viewer:

C:\> regsvr32.exe /u C:\Windows\System32\cabview.dll

Register (enable) CAB file viewer:

C:\> regsvr32.exe cabview.dll

Register DAO 3.6 (Data Access Objects):

C:\> regsvr32.exe "C:\Program Files\Common Files\Microsoft Shared\DAO\DAO360.DLL"

“I was planning to go into architecture. But when I arrived, architecture was filled up. Acting was right next to it. So I signed up for acting instead” ~ Tom Selleck (on his college registration experience)

Related commands

MSIEXEC - Microsoft Windows Installer.
RUNDLL32 - Run a DLL command.
Q249873 - Regsvr32 usage and error messages.