Why is Visual Studio skipping over my method when debugging?

Question

I'm attempting to debug into a method in a library (which was installed via NuGet, if that matters), and Visual Studio is skipping over it with the message:

Step into: Stepping over method without symbols 'Cpi.Net.SecureMail.CryptoHelper.FindCertificate'

I have a symbol server source added in the debug settings, and when I first debugged the program, it told me it was downloading the symbols for this library. I have verified that the symbols were indeed downloaded, as they show up in my symbol cache directory.

Thanks to SLaks, I know now that the PDB that has been downloaded from the symbol server is apparently in an obsolete format. If I retrieve the PDB directly from TeamCity's build artifacts, the debugging works.

So, it appears, that somehow, or for some reason, the PDB file is being altered either through the NuGet packaging process, or through the Symbol Server download process (ProGet).

The scope of the question has now, apparently, widened significantly.

Answer 1

It turns out that ProGet is indeed mangling the PDB file, in order to have it point to the source server instead of the local build folder for the source files. For some reason, ProGet is creating a PDB that Visual Studio doesn't like. Inedo and I haven't been able yet to nail down why.