Error: The assembly "c:\MyAssembly.dll" could not be converted to a type library

Question

I'm trying to build my project and I've suddenly started getting the following error when the project builds and the "Register for COM interop" property is ticked.

The assembly "c:\MyAssembly.dll" could not be converted to a type library. Type library exporter encountered an error while processing 'SomeType, MyAssembly'. Error: Referenced type is defined in managed component, which is imported from a type library that could not be loaded (type: 'OtherType'; component: 'c:\OtherAssembly.dll').

Nobody else on the team gets this error, its just me! Clearly I have done something odd to my machine, however the brute force approach of completely removing / deleting and re-adding everything I could think of made no difference, and so I am resigned to actually understanding this error (what a drag!)

So:

• What does this error actually mean
• Where should I look next for additional / more specific diagnostic information on what is wrong?

Foreboding

1. Does the project have any external dependencies that are not configured properly on your machine? 2. What does OtherType look like? – Bamako

@jgauffin, your going to need to be more specific I'm afraid - 1. My guess is yes because its broken, 2. Its an interface, other than that I'm not aware of any notable features. – Foreboding

Answer 1

In my case, I had a com exposed dll (I changed the guid) that was registered using regasm. I had to use the following command to un-register the assembly and then I was able to build the project successfully.

c:\Program Files (x86)\Microsoft Visual Studio 10.0\VC>regasm /u "C:\some-vs-project\bin\Debug\some-vs-dll.dll"

Also if you changed the GUID you need to make sure your NOT using the same GUID in the assembly.cs that your using in your class. I used the same GUID in both the class declaration and assembly and that causes the same error as well.

Rashida

Thank you, thank you, thank you! That last part about reusing the guid fixed my issues as well. :) – Fuqua

Answer 2

I had exactly the same problem. It was fixed magically by changing the target platform from x86 to Any CPU

Eloyelreath

Answer 3

I had this problem to. I just did the same, gactutil /u (for the uninstall) and gacutil /i (for the install) and the problem was solved

Frisket

Answer 4

In my case, this error occured because I had manually registered a COM-server via regsvr32. When I later moved the folder containing the dll, I forgot to update the registry (i.e. unregister and re-register the COM-server).

Reregistering the server fixed the error.

Verenaverene