You can use the Regsvr32 tool (Regsvr32.exe) to register and unregister OLE controls such as DLL or ActiveX Controls (OCX) files that are self-registerable.


Regsvr32 [/u] [/n] [/i[:cmdline]] dllname

/u – Unregister server

/i – Call DllInstall passing it an optional [cmdline]; when used with /u calls dll uninstall

/n – do not call DllRegisterServer; this option must be used with /i

/s – Silent; display no message boxes

Further information can be found at Also see the Wikipedia article about WoW64 at

When you attempt to run Regsvr32.exe to register a 32-bit dynamic-link library (DLL) on a 64-bit version of Windows, you may receive the following error message:

“filename.dll  is not an executable file and no registration helper is registered for this filetype”

This is because on a 64-bit version of a Windows operating system, there are two versions of the Regsv32.exe file:

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

and the 64-bit version is run by default. To resolve this issue, run Regsvr32.exe from the %SystemRoot%\Syswow64 folder.