Error message on 64-bit windows when you try run regsvr32.exe?

When you attempt to run Regsvr32.exe to register a 32-bit dll (dynamic link library) on a 64-bit version of Windows, you receive the following error message: Filename.dll is not an executable file and no registration helper is registered for this file type. This behavior is by design. This behavior occurs because the Regsvr32.exe file in the System32 folder is a 64-bit version. When you run Regsvr32 to register a DLL, you are using the 64-bit version by default.

To resolve this issue, run Regsvr32.exe from the %SystemRoot%\Syswow64 folder. For example, type the following commands to register the DLL:

cd \windows\syswow64
regsvr32 c:\filename.dll

Please note that the Syswow64 folder contains the 32-bit versions of Windows program files and DLLs.

Hope this helps.

• Anonymous
  September 28, 2010
  I am adding this with the respect to my previous blog post regarding error message on 64-bit windows

• Anonymous
  January 02, 2012
  Thanks. On Win7 regsvr32.exe works for "both" 32/64 bit DLLs because it automatically spawns the proper of the two regsvr32.exe files. See www.differentpla.net/.../things-i-learnt-week-regsvr32exe-windows-x64 However, on my Win7/64bit system exactly this is not working, and I don't know why. Doing it "manually" as you've described works though.