Class not registered Error


Running an application from Visual Studio 2012 on 64-bit computers, displays the following error message:

Retrieving the COM class factory for component with CLSID {F2D4F4E5-EEA1-46FF-A83B-A270C92DAE4B} failed due to the following error: 80040154 Class not registered (Exception from HRESULT: 0x80040154 (REGDB_E_CLASSNOTREG))

I am using Inventor packandgo dll library in visualstudio.

Anyone know what is the error?

asked on Stack Overflow Aug 1, 2013 by Arun • edited Aug 2, 2013 by Arun

10 Answers


My problem and the solution

  1. I have a 32 bit third party dll which I have installed in 2008 R2 machine which is 64 bit.

  2. I have a wcf service created in .net 4.5 framework which calls the 32 bit third party dll for process. Now I have build property set to target 'any' cpu and deployed it to the 64 bit machine.

  3. When Ii tried to invoke the wcf service got error "80040154 Class not registered (Exception from HRESULT: 0x80040154 (REGDB_E_CLASSNOTREG"

  4. Now Ii used ProcMon.exe to trace the com registry issue and identified that the process is looking for the registry entry at HKLM\CLSID and HKCR\CLSID where there is no entry.

  5. Came to know that Microsoft will not register the 32 bit com components to the paths HKLM\CLSID, HKCR\CLSID in 64 bit machine rather it places the entry in HKLM\Wow6432Node\CLSID and HKCR\Wow6432Node\CLSID paths.

  6. Now the conflict is 64 bit process trying to invoke 32 bit process in 64 bit machine which will look for the registry entry in HKLM\CLSID, HKCR\CLSID. The solution is we have to force the 64 bit process to look at the registry entry at HKLM\Wow6432Node\CLSID and HKCR\Wow6432Node\CLSID.

  7. This can be achieved by configuring the wcf service project properties to target to 'X86' machine instead of 'Any'.

  8. After deploying the 'X86' version to the 2008 R2 server got the issue "System.BadImageFormatException: Could not load file or assembly"

  9. Solution to this badimageformatexception is setting the 'Enable32bitApplications' to 'True' in IIS Apppool properties for the right apppool.

answered on Stack Overflow Sep 8, 2015 by Waheed • edited Sep 8, 2015 by Rohit Gupta

The problem is that the DLL is registered on the 32 bit version of the windows registry, and the application is using the 64 bit version.

Solution: Go into the Project Properties, Compile tab and click "Advanced Compile Options...". Change "Target CPU" to x86, click OK, save and try again.


Has worked for me with an VB 6 COM DLL invoked from a .Net 4 Winforms application

answered on Stack Overflow Jan 27, 2014 by Mariano Quevedo • edited May 31, 2016 by Mariano Quevedo

Somewhere in the code you are using, there is a call to the Win32 API, CoCreateInstance, to dynamically load a DLL and instantiate an object from it.

The mapping between the component ID and the DLL that is capable of instantiating that object is usually found in HEKY_CLASSES_ROOT\CLSID in the registry. To discuss this further would be to explain a lot about COM in Windows. But the error indicates that the COM guid is not present in the registry.

I don't much about what the PackAndGo DLL is (an Autodesk component), but I suspect you simply need to "install" that component or the software package it came with through the designated installer to have that DLL and appropriate COM registry keys on your computer you are trying to run your code on. (i.e. go run setup.exe for this product).

In other words, I think you need to install "Pack and Go" on this computer instead of just copying the DLL to the target machine.

Also, make sure you decide to build your code appropriate as 32-bit vs. 64-bit depending on the which build flavor (32 or 64 bit) of Pack And Go you install.

answered on Stack Overflow Aug 1, 2013 by selbie • edited Jan 22, 2016 by Sebas

In 64 bit windows machines the COM components need to register itself in HKEY_CLASSES_ROOT\CLSID (64 bit component) OR HKEY_CLASSES_ROOT\Wow6432Node\CLSID (32 bit component) . If your application is a 32 bit application running on 64-bit machine the COM library would typically look for the GUID under Wow64 node and if your application is a 64 bit application, the COM library would try to load from HKEY_CLASSES_ROOT\CLSID. Make sure you are targeting the correct platform and ensure you have installed the correct version of library(32/64 bit).

answered on Stack Overflow Aug 2, 2013 by Rajesh

Long solved I'm sure but this might help some other poor soul.

This error can ocurre if the DLL you are deploying in the install package is not the same as the DLL you are referencing (these will have different IDs)

Sounds obvious but can easily happen if you make a small change to the dll and have previously installed the app on your own machine which reregisters the dll.

answered on Stack Overflow Oct 11, 2017 by apc

I had the same problem. I tried lot of ways but at last solution was simple. Solution: Open IIS, In Application Pools, right click on the .net framework that is being used. Go to settings and change 'Enable 32-Bit Applications' to 'True'.

answered on Stack Overflow Apr 4, 2019 by Sunil Xtha

I had run into the same problem. I added reference of Microsoft.Office.Interop.Excel COM component's dll but Office was not installed on my system it wont give compile time error. I moved my application to another system and ran worked successfully.

So, I can say in my case it was the system environment which was causing this issue.

answered on Stack Overflow May 9, 2019 by Ankur Bhutani

I had this problem and I solved it when I understood that it was looking for the Windows Registry specified in the brackets.

Since the error was happening only in one computer, what I had to do was export the registry from the computer that it was working and install it on the computer that was missing it.


I was getting the below error in my 32 bit application.

Error: Retrieving the COM class factory for component with CLSID {4911BB26-11EE-4182-B66C-64DF2FA6502D} failed due to the following error: 80040154 Class not registered (Exception from HRESULT: 0x80040154 (REGDB_E_CLASSNOTREG)).

And on setting the "Enable32bitApplications" to true in defaultapplicationpool in IIS worked for me.

answered on Stack Overflow Nov 22, 2018 by Deeku • edited Nov 22, 2018 by Gourav Joshi

For me, I had to install Microsoft Access Database Engine 2010 Redistributable and restart my computer.

answered on Stack Overflow Nov 15, 2019 by Demodave

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