ASP.NET error 80040154 Class not registered (Exception from HRESULT: 0x80040154 (REGDB_E_CLASSNOTREG))


I have built an ASP.NET web application (that houses a Silverlight 4 app) and it utilizes a couple of COM dlls. The dlls are registered (verified by finding the CLSIDs in the registry, and seeing the classes within the CLSIDs), and they are located in a directory that has full control for all users.

When I run the VS debug using the localhost method, everything runs fine, but when I change it to use IIS hosting, it throws the error:

Retrieving the COM class factory for component with CLSID {006CA725-8B67-11D4-A067-FFF276E93345} failed due to the following error: 80040154 Class not registered (Exception from HRESULT: 0x80040154 (REGDB_E_CLASSNOTREG))

I am using Win7 64-bit, and I have enabled the appilcation pool for the site in IIS to allow 32-bit applications.

Not sure what else to try. The dlls are provided to us by a 3rd party manufacturer to calculate their product performance (which we need to help calculate our product performance), so I am unable to rebuild them in .NET (and the manufacturer is not changing them since they would then have to go through the re-certification process).

Thanks, Chris
asked on Stack Overflow May 27, 2011 by Chris

1 Answer


You are trying to embed a 32-bit ocx in a 64-bit application.

Your application will probably run just fine if you force to run as a 32-bit application on a 64-bit OS ... project properties -> build -> Platform Target = x86

answered on Stack Overflow Nov 13, 2013 by Kiran.Bakwad

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