The type library importer encountered an error during type verification

Question

I am writing a C# application which has several COM references. When I attempt to build it I get the following error for some of them:

c:\WINDOWS\Microsoft.NET\Framework\v3.5\Microsoft.Common.targets(1418,9): error MSB3303: Could not resolve COM reference "70850f66-869f-44a0-88e7-b0460a7e3bf3" version 0.1. The type library importer encountered an error during type verification. Try importing without class members.

The application is still built and runs successfully.

What does this error message mean, and how can I fix it?

Answer 1

By running TlbImp myself on the offending files I was able to determine the cause of the error. TlbImp is located somewhere like:

C:\Program Files\Microsoft SDKs\Windows\v6.1\TlbImp.exe

I ran it against the TLB file that was generated when I compiled my COM DLL, and I received a more detailed error message than what Visual Studio had told me.