Retrieving the COM class factory for component with CLSID {XXXX} failed due to the following error: 80040154

It sounds like your service was built against 'Any CPU', causing you errors on 64-bit where you are using COM components. You need to build it for x86.

The website is probably running as a 32-bit process which is why it can use the component. Building your solution against x86 will force your service to run as 32-bit.

The problem is that the server process is 64 bit and the library is 32-bit and it tries to create the COM component in the same process (in-proc server). Either you recompile the server and make it 32-bit or you leave the server unchanged and make the COM component out-of-process. The easiest way to make a COM server out-of-process is to create a COM+ application - Control Panel -> Administrative Tools -> ComponentServices.

I found that my problem related to the actual registration of the DLL.

• First run "Regedit.exe" from a CMD prompt (I raised it's security level to Administrator, "just in case")
• then search the Registry (by clicking on "Edit/Find" in the RegEdit menu or by pressing Ctrl+F) for the CLSID showing in the error message which you received regarding the COM class factory. My CLSID was 29AB7A12-B531-450E-8F7A-EA94C2F3C05F.
• When this key is found, select the sub-key "InProcServer2" under that Hive node and ascertain the filename of the problem DLL in the right hand Regedit frame. showing under "Default".
• If that file resides in "C:\Windows\SysWow64"(such as C:\Windows\SysWow64\Redemption.dll") then it is important that you use the "C:\Windows\SysWow64\RegSvr32.exe" file to register that DLL from the command line and NOT the default "C:\Windows\System32\RegSvr32.exe" file.
• So I ran a CMD prompt (under Administrative level control (just in case this level is need required) and type on the command line (in the case of my DLL): C:\Windows\SysWow64\RegSvr32.exe c:\Windows\SysWow64\Redemption.dll the press enter.
• Close the command window (via "Exit" then Restart your computer (always use restart instead of Close Down then start up, since (strangely) Restart perform a thorough shut down and reload of everything whereas "Shut Down" and Power-Up reloads a stored cache of drivers and other values (which may be faulty).
• Whenever you register a DLL in the future, remember to use the SysWow64 "RegSvr32.exe" for any DLL stored in the C:\Windows\SysWow64 folder and this problem c(if it is caused by incorrect registration) should not happen again.

In my case, I'm producing ms office file like word or excel, I run Win+R and execute dcomcnfg, in the DCOM Config, besides select OFFICE related name item (such as name contains Excel or Word or Office) and Open the properties, select Identity tab and select the interactive user. as this answer,

My error message show CLSID {000209FF-0000-0000-C000-000000000046}, so I have to try to find this specific CLSID in DCOM Config, and it does exsits, and I select it and follow same step set the interactive user, then it works.

Accepted answer, changing target platform to x86 did not work in may case!

When I have installed crystal report for visual studio and crystal report runtime engine (64-bit) worked in my case!

Some other suggests that, this problem could be resolved by installing both 32-bit and 64-bit runtime engine!

You may give a try!